The Silverstone Classic meeting in July 2010 included a race for Grand Prix Masters F1 Cars 1966-1986 and the car pictured below in the pit garage is one of the cars that took part in that race.
It's a 1979 Lotus 80 and was driven in this race by Sid Hoole. Colin Chapman had started exploring the use of ground effect in his cars with the Lotus 78 of 1977 and the Lotus 80 was an attempt to maximise the benefits that it gave. The car was introduced at the 1979 Spanish Grand Prix where Mario Andretti finished in third place, but started in only two races after that, retiring both times. In the other races that season the team ran the Lotus 79 which had given Mario Andretti the 1978 World Championship. You can read about the Lotus 80 here.