Sebastian Vettel has won the last three championships in succession for Red Bull and the 25-year-old German leads the standings again as the only driver to have won twice in four races so far.
McLaren's Button, the last world champion before Vettel, has finished no higher than fifth this season while Hamilton, the 2008 champion, has had two third places since he moved to Mercedes.
Silverstone managing director Richard Phillips said on Wednesday that ticket sales for the June 30 race were down nearly 10 percent on last year, when 297,000 people attended over the three days despite flooded campsites and torrential downpours.
"If you look at the cycle on selling tickets...on the Monday after a grand prix Sunday you tend to see a spike. The weekend we had Lewis on the podium there was a spike and when you see Vettel there is less of a spike," he told Reuters, referring to demand for tickets for the British Grand Prix.
"I think the needle-movers (for sales) are going to be basically 'not Vettel'."
Britain had the biggest crowd of the season last year, with a record race day attendance of 127,000 and more people turning out on a Friday than on a Sunday in some parts of the world where Formula One has no tradition.
Eight of the 11 teams are based in Britain, including champions Red Bull, and last year saw seven different winners in the first seven races.
Former Formula One driver Derek Warwick, president of circuit owners the British Racing Drivers' Club, said the success of the British pair was crucial.
"When we know that Lewis and Jenson are coming into the grand prix off the back of a couple of wins, we see a massive spike in our sales," he said.
Phillips said they had probably reached the break-even point but the circuit needed to exceed that comfortably to recover some of the £40 million investment made on improvements in the past five years.
Hundreds of thousands have been spent since last year's 'wake-up call', with improved drainage to campsites, ditches re-profiled and park and ride spaces added.
BRDC chairman Stuart Rolt said the search for outside investors to help fund development was continuing after an exclusivity agreement with an unidentified partner, believed to be a Qatar-based group, ended last year.
"We are still talking to people very positively and we keep going," he said. "There is no threat to the grand prix if we don't find an investor, everything just slows down..."
Rolt said the process had been frustrating due to the difficult economic climate, and a clash between what property developers wanted and the aims of the BRDC, but hoped "to get something done" this year.
He would not give details about any potential partners.
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