If you think about the most memorable moments in the history of Formula One, how many happened in qualifying? There would be some - Ayrton Senna's 1988 Monaco pole lap for example - but the lion's share would be from races.

This is for obvious reasons. F1 is about racing, first and foremost. Qualifying does not give you the wheel-to-wheel action you get on Sundays. And, of course, no points are scored on Saturday.

But there is something pure about man and machine racing flat out against the clock, with no strategic distractions.

Yet, even for the most enthusiastic fans, qualifying is worth watching but it is not an unmissable event. In 2018, however, it has been utterly compelling.

A combination of factors in the last year or so has led to Saturday afternoons being close to their peak. At some rounds this season they have provided a greater thrill than the actual race.

The Canadian Grand Prix is a great example. In Montreal we went into Q1 with six drivers from three teams challenging for pole. Max Verstappen had topped all three practice sessions beforehand.

We finished with Sebastian Vettel on pole, just 0.093 seconds ahead of Valtteri Bottas. It was marginal all the way down to Daniel Ricciardo in sixth. The Australian was just 0.352 seconds away from Vettel's time. This represented the smallest margin from first to sixth since the 2014 Singapore Grand Prix.

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Silverstone wasn't too bad, either, with 0.098 seconds separating the top three - and just 0.044 seconds between first and second - as Lewis Hamilton took a stunning last-gasp pole position in front of an adoring, rapturous home crowd.  It was breathtaking stuff and great sporting drama.

F1 finds the perfect format...but not without tinkering

To understand the resurgence of qualifying you have to look at several factors. The first is the format, which has to be successful in both intention and execution.  Many have failed in one way or another. The success of the current one has not come without significant modification and some very flawed and failed experiments on the way.

Who can forget the farce of the 2016 elimination system, aimed at shaking up the grid? With this change, drivers were removed at 90 second intervals towards the closing stages of each session until there were two drivers competing for top spot in Q3. All fine, in theory.

The problem was that it was so confusing that not even the teams knew what was happening. The drivers that were eliminated were often not on track at the time. It created confusion not excitement and was a rotten failure. Imagine how baffling it would have been to someone watching F1 for the first time. For the sake of everyone's sanity, it was dropped after just two rounds.

Most format changes have come since 1996, when qualifying moved to a one-hour format on Saturday alone. Before this there were two sessions; one on Friday and then a second on Saturday. The fastest time across the two sessions would take pole.

This was fine but flawed. If the conditions worsened in the second session, everyone would sit in their garages, twiddling their thumbs with the outcome a foregone conclusion. Far from ideal if you actually want people to watch.

In 1997, the one-hour, 12-lap maximum session was introduced, all happening on Saturday. It was better but still far from optimal. The main issue was limited running from the top teams in the early part of the session, as they waited for the track to "rubber in" and to take advantage of the best conditions.

Much of the hour was spent watching backmarkers desperately trying to get within the 107 per cent time. Handy for the sponsors of Arrows or Minardi to gain TV exposure but not so useful for the fans at the track or watching at home.

Since then we've had the two-session one-lap shootout (2003-2004) where drivers had one qualifying lap only, with one driver on a flying lap at a time. Shoot or bust. All or nothing. This was exciting - with massive consequences for anyone who stuffed up their lap - but it was also imperfect. It was also open to drivers gaming the system (the running order was determined either by an initial session or the results of the previous race) and occasionally determined by changeable weather.

In 2005 came another short-lived aggregated two session system, which was discarded after six races.  The decision to move to a one-hour three-part Saturday session came in 2008. With three sessions (Q1, Q2 and Q3) and eliminations at the end of the first two, the aim was to maximise excitement and add a pinch of jeopardy. It succeeds in both.

The current format (there was a slight tweak) has been in place since 2010. But it is not sufficient to create great sessions. There is only so much the FIA can do with the format.  The main reason 2018 - and to a lesser extent 2017 - has been so exciting has been the closeness of the teams across the grid.

That is borne out by the statistics. By several metrics, the gap has closed in 2018, and also in 2017. These apply at the front of the grid as well as in the midfield. By looking at the development of the gaps between certain positions in on the grid we see how much closer, and consequently more unpredictable from race-to-race, qualifying has become.

The data does not include wet sessions, which distort the average and are unrepresentative.  Some caveats here, too, in that some of the longer tracks (Spa, Singapore, Abu Dhabi) come later in the year, so 2018's data is not 100 per cent representative.  While these figures do not tell us absolutely everything, they help us to see trends. And those trends are heading in one direction.

It's closer at the front...

As seen in the table below, there has been a healthy closing of the gap between first and second on the grid. After sitting around 0.230-0.300 seconds from 2013 to 2016, there was a marked improvement in 2017, when Ferrari had a car capable of challenging Mercedes throughout the season. The gap was never more than six tenths of a second in 2017.  In 2018 it is down again to 0.165 seconds from the first 11 races.

The first race of this season in Australia - where Lewis Hamilton took pole ahead of Kimi Raikkonen by 0.664 seconds - appears to be an outlier.  But that is frequently the case at the season start as the teams fight to understand the strengths and weaknesses of their cars. In the subsequent 10 races the gap has only been more than 0.180 seconds three times. Four times it has been under a tenth of a second.

In 2017 this happened seven times in 19 rounds. So, 11 times in the last 30 races (or 36.7 per cent of the time) the gap from first to second has been below 0.180 seconds.  In the previous four seasons (total 77 rounds, excluding wet sessions), from 2013-2016, this occurred 13 times, or just under 17 per cent of the time.

This has been as a result of Ferrari becoming genuine challengers to Mercedes. At most weekends there have been four drivers, in fairly equal machinery, capable of topping the timesheets. For most of the turbo hybrid era it was two drivers on the same team: Mercedes.

The gap from the first to the fourth placed man has also reduced since 2013 - by just under two tenths of a second from last year and by around four tenths from 2016.  Although Red Bull have not matched Ferrari or Mercedes on raw pace, Monaco aside, they have challenged the second row of the grid at most rounds. This year could end up even closer than 2013, where the average gap from first to fourth was just over six-tenths of a second.

2013 has parallels with this season, with several cars challenging for the top step of the podium. In 2013, no team won two races in a row until over half-way in the season and four constructors won in the first six rounds.

Naturally, the closer the teams are in performance, the more unpredictable the session. From 2014-2016 we had complete Mercedes dominance, as Lewis Hamilton and Nico Rosberg took a combined 46 poles from a possible 49. It was boring and predictable beyond belief.  In 2017 their power waned slightly, with just 15 poles in 20 races. Yet, although the difference between first and second shortened, it was still Mercedes who took three-quarters of the pole positions.

Not this year. In the current campaign they have been fastest on Saturday only five times in the first 11 rounds. On raw pace alone - measured in qualifying trim - the average percentage gap over the course of the year between Mercedes and Ferrari is just0.032 per cent. Or, to convert it into time: on a theoretical 90-second lap time, a negligible 0.028 seconds.

This helps illustrate why qualifying has been worth watching for the first time in years. There is genuine uncertainty as to who will emerge fastest on Saturday and not just within one team. With the difficulty of overtaking, the predominance of one-stop races and an incredibly close championship it means a good or bad result on Saturday has much more of an impact on the championship. A tiny mistake in Q3 can have disproportionate consequences for the race and championship.

After all, who really cared if Sebastian Vettel took pole in the 2015 Singapore Grand Prix? Okay, it was the only non-Mercedes pole of the season but at that point he had little chance of winning the championship. It was an upset that lacked any real significance.

Extending the time gap from first to sixth brings about similar results: a reduction in two or so tenths of a second in 2018, after four years where the difference was fairly constant. As the development race continues at great pace there is a good chance that once this season is over the average difference from pole to sixth will be under a second.

Small gaps in the midfield help the bigger picture

Although the most exciting part of qualifying should be the final runs of the drivers aiming to start first on Sunday, there has been drama throughout the field in 2018.  This is another consequence of a good format. This has been possible with a field which is in effect two-tier: Mercedes, Ferrari and Red Bull at the front and then everyone else behind them, but not far apart at all.

Haas, the fourth quickest team on raw pace in 2018, are closer to the ninth best, Sauber, than they are to Red Bull directly ahead of them.  The difference between the top teams and the rest is stark. This is a problem for F1 as a spectacle.

But as long as the top three teams are separated by small margins and have machinery capable of winning on most circuits, as in 2018, the problem is not as exposed as it could be.

Addressing this gap needs immediate attention. Thankfully it is getting some, with Liberty Media's plans for the sport beyond 2020 aimed at reducing the advantage the big three have in money, resources and ultimately pace.

It is worth noting that no team outside Red Bull, Ferrari and Mercedes has won a race since the opening round of 2013, when Kimi Raikkonen triumphed for Lotus. The last pole for a driver outside of these teams came even further back, with Pastor Maldonado at the 2012 Spanish Grand Prix for Williams. We need occasional upsets, even in qualifying.

There are, at least, very small gaps among the "B-class" teams, which also aids the viewing experience on Saturdays. A two-tier championship is better than a three-tier one and the resurgence of Sauber as a points-scoring force is much-needed.

Not knowing which of the midfield runners will be knocked out in Q1 and which could sneak into Q3 has also helped improve qualifying as a spectacle. Q1 becomes an almost dead session when you have a good idea who four of the five drivers who are going to be eliminated. Every team with the exception of Williams has at least two appearances in Q3 this season.

Looking at the average gap season-to-season from the 10th to the 16th placed driver in Q1 over the last three years we can again see that things are tighter this season. Small mistakes, whether from team or driver, can be costly and maybe even the difference between going out in Q1 and starting 17th or making it through to Q3 and starting 10th if your car has the pace. In a tight midfield fight, where resources are limited and prize money is so valuable, Saturday performance is critical.

'If it ain't broke' - why F1 bosses should avoid any rash changes

The combination of small gaps between the teams and an optimal format has led to qualifying being as good as it has been for a long time. Perhaps ever. As F1 bosses continue their planning for the future of the sport, they hoping to increase the spectacle for "stakeholders" (read: viewers) with new regulations and possible format changes. This is the right priority. It cannot just be what the teams want. But the full consequences of any changes need to be seriously considered, as they surely will be.

There has been talk of a reverse-grid qualifying sprint race to decide the main race's starting order, something suggested by F1's managing director of motorsport, Ross Brawn. The order for the qualifying race might be in reverse championship order. The final classification would decide the order of the grid. Again, the aim here is to employ that well-worn phrase, to "shake up the grid", produce uncertainty and overtaking as drivers in the top cars have to make their way through the field - as Lewis Hamilton did at Silverstone.

That would no doubt provide excitement but does it lack the integrity that F1 needs as the supposed pinnacle of motorsport? A Mercedes starting from 15th or 20th on the grid would be interesting, yes, but if it happened in numerous times a season it would cease to be a novelty. And perhaps "novelty" is the best way to describe this whole proposal, well-intentioned though it is.

It also raises many questions, such as cost and artificiality. Not that artificial aids to racing have been rejected. We have had the Drag Reduction System (DRS) since 2011, introduced to help overtaking. This year six races out of 11 have had another DRS zone added for the race. There has been little return on this.

Reactionary changes are unlikely to secure a sound and stable future for F1. There is a danger that F1 will introduce new formats, gadgets and regulations quicker than drivers, teams and - most importantly - viewers can keep up. All with no guarantee of long-term or even short-term improvement.

The biggest problems are in places other than the format. Having teams that can compete on equal terms is crucial to maximising excitement and, ultimately, viewing figures. That is why this year has had the closest and most nail biting qualifying sessions for years.

Leveling the grid and ending the uneven dominance of the top three teams should be the focus. As we have seen this year, sort this and everything else should follow. But F1 would be wrong to abandon such a successful format format for the sake of change.