And then it got wetter - and even wetter as the cars got back out on track. Of the sport's 20 drivers, only one didn't turn up.
Victory tomorrow would draw Hamilton level with Clark and Alain Prost on five British Grand Prix wins.
"Why go and start spending huge amounts of money, and it would have to be government money, to have a racetrack (in London)?"
The Finn produced a best lap of 1min 28.496sec - quicker than Hamilton's pole position time of 1:29.287 a year ago.
"Today's been a really good start to the weekend and it's great to be back here at Silverstone, " Hamilton said, before news of Bottas's grid penalty broke.
Hamilton had also done an excellent job in bringing his Mercedes home fourth after starting ninth on the grid due to a gearbox penalty. "You will have seen over the previous years how much I appreciate and respect that and try to give and enjoy the weekend with the fans and that doesn't change", said the 32-year-old who celebrated his win last year by jumping into the sea of fans gathered below the podium.
"That is where I feel I like to put my energy mostly. I've been proud and fortunate in the last few years to do that and the aim is to do that again this weekend", he said.
This is the most intense battle I've had through my whole racing career, the Mercedes driver told Martin Brundle and Simon Lazenby during the F1 Show.
Since Hamilton rejected the invitation, Valtteri Bottas was the only Mercedes driver to attend. They always have and I make no secret of that.
Valtteri Bottas continued his and Mercedes' strong start to the British Grand Prix by edging teammate Lewis Hamilton to the quickest time of Friday's second practice session.
Some form of cockpit protection is set to be introduced next season, with the shield, which was run for the first time yesterday, having emerged as the preferred option over the halo concept that was trialled previous year. "It turned out a great event, a fun event for us as well as for the people".
Asked if he would attend a similar promotional event in future, Hamilton responded: "I guess I'll decide when the time comes".
The FIA confirmed after the session that it would be investigating the block, putting Hamilton's pole position at risk, only for the stewards to opt against handing out a sanction.
There had been speculation before the weekend that Copse corner would be flat-out, but Hamilton said it was actually quicker to have a small lift and take it in seventh gear.