0km - Valverde was 1:59 down on Clarke, which puts him down to ninth on GC, 36 seconds behind the new red jersey Joaquim Rodriguez.
0km - The Contador-Froome-Rodriguez group crossed the line 1:04 down on Clarke. We're still waiting for a time check on Valverde.
0km - That's a first professional win for Simon Clarke of GreenEdge - and the second time Tony Martin has lost a sprint over a summit finish. The German lost to Juan Manuel Garate on the Ventoux back in the 2009 Tour.
0km - Valverde lost time to his main contenders at the finish so will lose the red jersey tonight. Full confirmation when we get it.
0km - Tony Martin was resigned to take second place, while Assan Bazayev managed to take third. We didn't see him at all on the final climb, but he was clearly still there for Astana. The chasing group comes home about a minute down, with Caja Rural's Marcos Garcia thinking he has won the stage, his arms aloft as he crosses the line.
0km - Simon Clarke goes on the outside and takes it easily! Victory for the Australian and GreenEdge.
0.5km - It's Martin who is on the front, with Australian Clarke on hsi wheel. Clarke probably has a bigger kick than the time trial specialist. This will be fascinating.
1km - Martin and Clarke enter the final kilometre and they're starting to play around. One of these two will win.
2km - The five chasing riders - Roche, Gerdemann, ten Dam, Zeits and one other - are in pursuit but it's probably too late.
2.5km - Valverde is not yet back with the group of main favourites as his titanic chase back on continues.
3km - The two leaders have 1:40 over the Roche chasing group, who themselves are 18 seconds ahead of the group of favourites. Euskaltel's Igor Anton is having problems and is off the back. It's Menchov and Moreno driving the pace for Katusha.
3.5km - Contador and Froome are back with the Rodriguez group. It's very confusing because the Spanish camera crews don't appear to be too clued up on what's happening.
4km - Martin and Clarke still have two minutes over the chasing riders. They have four kilometres to go but it's touch and go.
5km - Roche has pulled clear of Contador, Navarro and Froome and the Irishman rides solo in pursuit of Martin and Clarke. Roche is joined by Gerdemann, ten Dam and Zeits. Contador and Froome must have called a truce and sat up.
6km - Valverde is beginning to look pretty tired now. He made such an effort to get back in the race and will be suffering now. Lucky he has Intxausti with him. Fuirther up the road, Luis Angel Mate has been caught by the Contador group, as has Rosendo.
7km - The Contador quartet have just seven seconds on the Rodriguez chasing group. Roche is setting the pace now, on Saxo Bank work experience so to speak.
7.5km - It's Simon Clarke setting the pace on the front with Martin. Movistar's Benat Intxausti has dropped back to help out Valverde. Roche is having a super ride alongside his team-mates for next season, Contador and Navarro.
8km - No reaction from Rodriguez as yet as Contador rides with his team-mate Navarro as well as Froome and Roche further up the road. We're waiting for a time check on Martin and Clarke, the leaders. But Valverde is 50 seconds down on the Contador-Froome quartet.
9km - Valverde has reduced the gap to just 20 seconds now. But there's an attack on the front with Froome, Navarro, Roche and Contador pulling clear.
9.5km - An attack comes from Euskaltel on the front of the main bunch. It's Ivan Velasco, and he finds himself joined by Saxo's Daniel Navarro and Astana's Andrey Zeits.
10km - Valverde is passing the riders who have been shed by the main pack. He's riding at a strong pace and making some headway alongside Vacansoleil's Rob Ruijgh. Sky and Saxo are still on the front of the main pack.
10km - Valverde is riding in a group of about seven riders 40 seconds down on the main pack, which is being driven by Sky. The two leaders - Tony Martin and Simon Clarke - are 4:10 ahead of the peloton.
11km - The main peloton and chasing group are onto the final climb now as Martin and Clarke continue their double ride towards the summit. Valverde has attacked from the second group, which has already been blown apart.
12km - Resondo and Bazayev have now been dropped too, so we have Clarke and Martin in the lead. Back with the two pelotons, the gap is now 1:08 between the leading Contador-Froome group and the chasing Valverde group.
13km - Luis Angel Mate (Cofidis) is the first rider to crack on this early, steeper section of the climb. With the main peloton now just 5 minutes back, it looks like the Spaniard may not get that red jersey tonight after all...
14km - The leading five riders are onto the Cat.1 climb to Valdezcaray - 13.5km at 5.3%.
15km - Philippe Gilbert, with his yellow helmet, is driving the pace on the front of the leading peloton. The second group is now 50 seconds off the pace. It is being driven by a mixture of Liquigas, Movistar and Rabobank riders, all of whom seemed to be affected by the crash that occured just as Sky had started to up the tempo.
16km - The five leaders are approaching the final climb of the day. The first 3km of the climb is the really tricky part, then it levels out and the main problem becomes the wind.
17km - BMC have come to the front of the first peloton, with Ballan, Cummings and Gilbert pushing on hard. The Valverde chasing group is 32 seconds down still. And the break is apparently now just seven minutes ahead - so they must be tiring fast.
18km - In all that drama, we missed the second intermiate sprint, which Luis Angel Mate took ahead of Steve Clarke and Jesus Rosendo. Mate has won both sprints and the only climb so far today - he's smokin'.
19km - The gap back to the Valverde chasing group is 42 seconds. It's about half the peloton. Sky and Katusha continue on the front.
20km - We're approaching the final climb of the day. The likes of Froome, Menchov, Contador, Roche, Uran, Meyer, Monfort, van den Broeck and Rodriguez are all in the main peloton. The Valverde chasing group is 50 seconds off the pace. Meanwhile, the five-man break are still 12:20 up the road, oblivious of all the drama unfolding behind.
22km - The Valverde group is almost back on with the third large echelon. There are two more further up the road, the first one being led by Sky and Katusha. It will probably come back together, but there will be some very tired - and bruised - bodies going into the final climb.
23km - It's debatable if Sky should have sat up after that crash - it did occur because they had upped the tempo, and not the reverse. But still, Valverde will be fuming. He didn't go down hard, but needed a bike change. No news on the riders who did hit the deck hard - and a handful did so - but we'll keep you updated.
25km - There are at least four groups in the peloton, and then the small Valverde-Movistar chasing group more than a minute back.
28km - That crash, the wind and the Team Sky pace setting has created multiple echelons in the peloton. Valverde has one team-mate, Nairo Quintana, with him. Actually, he has three more now - and a Rabobank rider. Sky and Katusha are piling on the pressure.
30km - Team Sky are piling on the pressure on the front after that crash. The incident came right on the front of the peloton just as Flecha was upping the tempo.
32km - VALVERDE DOWN: Big crash in the peloton as the race leader hits the deck, alongside riders from Liquigas, GreenEdge and Saxo Bank.
40km - Movistar have completely knocked it off and now we have a mixture of teams on the front, none of whom seem overly concerned about the break. The winner of today's stage will certainly be one of the escapees.
45km - Team Sky are beginning to come to the front of the peloton, clearly shocked at Movistar's inability to set a tempo fast enough to reduce the deficit.
50km - The leaders pass through the rather ugly town of Haro with a gap of 13:16. There's no way they're going to be caught now.
55km - The break has just passed through the first intermediate sprint, which was taken by Luis Angel Mate (Cofidis) ahead of Assan Bazayev (Astana) and Jesus Resondo (Andalucia). The gap is still 12:42 so it looks like this group will stay out until the end now.
60km - Sean Kelly on the return of Alberto Contador: "For me he's a big champion. Yesterday he made the race interesting for everyone. He attacked seven times which was really exciting racing. He deserves his place in the peloton - he's served his time and is back. If others are allowed to do it, then why not him. Cycling is on the right road and from a doping point of view it's on the mend."
62km - The wind is pretty strong, which at least takes the edge off the fierce heat. Movistar still control the pace on the front of the peloton, but they're really taking it rather easy. The five leaders pass are into the Rioja wine region and the roads are surrounded by vines. They still have 12:30 over the peloton.
65km - The leaders have passed through the feeding zone with an advantage of 12:15 over the peloton. Luis Angel Mate is currently the virtual red jersey. The Cofidis rider trails Alejandro Valverde by 3:36 on the overall standings but Movistar don't seem too concerned about reducing the gap. In fact, if the tempo is not increased soon, this break could well stay out until the end.
70km - There are currently six Spanish riders in the top ten of the overall standings. Add to that two Dutchmen, a Brit and a Colombian.
75km - Javier Aramendia, who had tried to join the five leaders earlier on in the stage, has dropped back to see the medical car. The temperature is up to 38 degrees now with some strong crosswinds coming from the right. The lead is now 12 minutes for the five escapees.
80km - The five leaders - Jesus Rosendo (Andalucia), Simon Clarke (Orica-GreenEdge), Tony Martin (Omega Pharma-Quick Step), Luis Angel Mate (Cofidis) and Assan Bazayev (Astana) - continue on this long, flat stretch of the stage. They now have 11:10 over the pack and will soon tackle a short uncategorised bump before the next long and flat segment of the stage. After two intermediate sprints we will then have the deciding climb, the Cat.1 ascent to the ski resort of Valdezcaray.
85km - Puncture for Sergio Carrasco of Andalucia. The Spaniard was involved in yesterday's break. The thermometre is rising: 37.5 degrees now. The gap is back to 10:40 for the five leaders.
90km - Yesterday, Contador put in a series of attacks - seven in total - and could only be followed by Rodriguez, Valverde and, just, Froome. The win looked to be going to Rodriguez but the Katusha rider appeared to stop pedalling and allowed Valverde through. J-Rod admitted afterwards that he was "p off" with what happened and said it was his fault. "I won't ever make the same mistake again," he vouched.
95km - Alberto Contador was cautious ahead of today's stage. "If the wind blows on the final ascent it will be difficult to attack (like yesterday) because the climb is not very hard," he said, stressing that the stage win may be decided by "a group of more than ten riders".
100km - The temperature is up to 33 degrees as the five leaders complete the descent with just over nine minutes to play with over the peloton.
105km - With those 10 points, Mate draws level with Alejandro Valverde on the KOM standings. They trail Dutchman Pim Ligthart (Vacansoleil-DCM) by one slender point. There are double points available for the second climb of the day because it's a summit finish - so whoever wins today will probably take the polka dot jersey, provided they're not in red.
107km - Luis Angel Mate (Cofidis) is the first to cross the summit of the Cat.1 Puerto de Orduna. He is followed by Simon Clarke (GreenEdge), Jesus Rosendo (Andalucia), Tony Martin (OPQS) and Assan Bazayev (Astana) in that order. The lead is down to 9:42.
108km - Frenchman David Boucher (FDJ-BigMat) has withdrawn from the race. Boucher was last on GC following an accident in stage two. Not a nice way to end his debut Grand Tour.
111km - We're already onto the Cat.1 Puerto de Orduna climb - a 7.7km ascent with an average gradient of 7.8% and a maximum gradient of 11.7%. The gap is down to 10:45 with Movistar controlling the tempo on the front of the pack.
112km - The first rider in this group is 30-year-old Jesus Rosendo, who has been at Andalucia throughout his career. Rosendo is without a professional win to his name, although was briefly kind of the mountains in the 2008 Vuelta. In 2010 Rosendo was caught up in controversy after an investigation showed him to have irregular blood values. He was suspended by his team but claimed his readings were high owing to haemorrhoids.
113km - Kazakh rider Assan Bazayev, 31, is the current national road race champion, six years after he first won the same prize. His only professional stage win came in 2006 in the Tour of Germany. Australian Simon Clarke was a former Astana team-mate of Bazayev for one year before joining GreenEdge in 2012. The 26 year old is a former junior national track champion. He also won the U23 national road race in 2008 as well as a stage in the Tour of Japan.
114km - Spain's Luis Angel Mate (Cofidis) was one of the most agressive riders in last year's Vuelta. The current virtual red jersey, Mate had a tricky Tour de France after a first week marred by crashes and bronchitis. The 28 year old has never won a stage in a Grand Tour although this year he took both the sprint and mountains classification, oddly enough, in the Vuelta a Andalucia.
115km - The best-known rider in the break is German Tony Martin, the world time trial champion. The 27 year old will be the hot favourite for next week's time trial - Martin won last year's ITT in the Vuelta and picked up a silver medal in the London 2012 Olympics behind Bradley Wiggins. He did, however, crash badly in stage one of the Tour de France, breaking his scaphoid. He has been playing catch up ever since, but evidently is back to top form by this showing.
118km - Average speed for the first hour of racing today was 39.8km/h. The gap is 11:50 for the five leaders. Time to bring you some more information on the escapees...
120km - Game over for Javier Aramendia, who is taken back into the peloton. Brave effort from the Caja Rural rider to join the leaders, but he stood no chance once the quintet got into their stride.
125km - The lead has past the 10-minute mark and is now a huge 11:32. Poor Aramandia seems to have given up: the Caja Rural rider is 9:40 down on the five leaders and will soon be taken back by the peloton.
126km - "I'll try and keep going in the lead as far as I can, but after such a great start to the race, anything we get from here on is a bonus," Valverde said. "Contador was definitely the strongest but Rodríguez and I could get back up to him every time he attacked. It (the climb) cost Froome a little bit, but with that time trial in the second week it's going to be very difficult to keep him under control."
128km - "It's incredibly difficult to beat a rider like Rodríguez, he deserved the win as much as me, but maybe he was a little bit over-confident and I just managed to do it," Valverde said after his stage win yesterday. "Movistar have won the opening team time trial and this stage as well, we've kept the lead for the last three days, we can be more than happy with what we've achieved."
130km - The lead is ballooning quite fast now: it's up to nine minutes, with Aramandia cursing his luck and riding five minutes down on the leaders but four minutes ahead of the pack. No concern shown from Movistar yet - Luis Angel Mate is the virtual red jersey but there's still a long way to go, plus both of those two climbs.
133km - A reminder of the jerseys: Spain's Alejandro Valverde (Movistar) is in the red leader's jersey after his victory (and bonus seconds) yesterday; German youngster John Degenkolb (Argos Shimano), winner of stage two, is in the green points jersey - tied at the top with 25 points alongside Valverde; Dutchman Pim Ligthart (Vacansoleil-DCM) crossed three minor climbs yesterday in pole position and is now in the blue polka dot KOM jersey - he leads Valverde by one point.
135km - The temperature is up to 30 degrees now - and the gap over the peloton is 6:15. Poor Aramandia is making little headway, mind. The Spaniard still rides solo in pursuit of the five leaders, 2:30 down.
140km - The lead continues to grow as the escapees now have 5:20 on the peloton, making Mate the virtual red jersey. That man Aramendia, who was part of the main break in stage two, is still trying to catch up with the leaders, but rides at 1:30. We have a series of rolling hills before the first climb of the day. Then two intermediate sprints - with bonus seconds - before the final climb to the finish.
145km - Our five leaders - Jesus Rosendo (Andalucia), Simon Clarke (Orica-GreenEdge), Tony Martin (Omega Pharma-Quick Step), Luis Angel Mate (Cofidis) and Assan Bazayev (Astana) - have 4:30 on the peloton, with Javier Aramendia (Caja Rural) riding solo in pursuit at 1:30.
150km - The five leaders have about two minutes on the peloton, with lone rider Aramendia stuck right in between. None of these men are a threat on GC: Spaniard Luis Angel Mate is the best placed in the overall standings, 3:36 down on Alejandro Valverde.
154km - Kazakhstan's Assan Bazayev (Astana) has joined the leaders, while Javier Aramandie of Caja Rural is in pursuit of the five-man break. The temperature is much lower than yesterday: 27 degrees Celsius at the moment.
155km - The first climb of the day - the Cat.1 Puerto de Orduna - comes after 44km of racing. It's 7.7km long at an average gradient of 7.8%. The final climb is on a new wide road and it's not as steep as the concluding climb yesterday, which saw Alberto Contador put in a massive seven attacks. It's 13km long but with an average gradient of 5.2%. The steepest part is at the start where the slope is 9%.
157km - There's an early attack from four riders: Jesus Rosendo (Andalucia), Simon Clarke (Orica-GreenEdge), Tony Martin (Omega Pharma-Quick Step) and Luis Angel Mate (Cofidis). They have about eight second over the pack.
160km - They're off! The 160.6km stage is underway. Two categorised climbs on the agenda today: the Cat.1 Puerto de Orduna and then the final Cat.1 ascent to the finish. Once again, it's a short and sharp stage - which should encourage attacking riding.
12:25 - The remaining 197 riders are pedalling through the neutral section of today's stage. Just the one withdrawal so far in this year's race: Italian Enrico Gasparotto (Astana), who crashed during the technical team time trial in Pamplona on the first stage of the race, breaking a collarbone.
12:20 - Alejandro Valverde leads compatriot and Movistar team-mate Benat Intxausti by 18 seconds on GC, with Joaquim Rodriguez in second place, a further second down. Chris Froome is fourth, at 20 seconds, and Alberto Contador in fifth, at 24 seconds. Overall standings
12:15 - Yesterday, Spain's Alejandro Valverde pipped compatriot Joaquim Rodriguez to win stage three of the Vuelta a Espana and move into the red leader's jersey. A late dig saw Movistar's Valverde rider surge past Rodriguez of Katusha on the closing straight of the 155km hilly stage through the Basque region in northern Spain. Report: Valverde takes Vuelta stage 3 win and red jersey
12:10 - Welcome to live coverage of stage four of the Vuelta a Espana - a 160.5km trek through the Pais Vasco mountains which culminates in a Cat.1 climb to the ski station of Valdezcaray.