As Alan and Richard say, International Trophy, Silverstone. The race was held on Saturday 29th April 1967. I understand that the fire occurred on the previous Wednesday, which would make it 26th April.
Have a look at this earlier thread: The Pearce-Martin F1 car
which includes this post featuring some photos of the burnt-out transporter. Sadly, two of them have vanished, but it's quite clear from the one that's left that it's the same incident as in Gary's photo. Note the photographer on the left; is he perhaps taking Gary's photo?
Thanks for advice on adding images. I have attached the Pearce ones. These came from the archives of LAT. If there is any objection to them being shared then I will remove them. Farcinating stuff.
Will post the Shannon ones seperately.
Edited by Tim Murray, 21 December 2013 - 10:30.