The MP4-29H pictured here is based closely on the MP4-29 which Jenson Button and Kevin Magnussen have been driving all season, starting strong with a double podium finish in Australia but dropping sharply off over the course of the rest of the season since. The main difference (as far as we know, anyway) is that this car has swapped its Mercedes-AMG PU106A hybrid power unit for the new engine which the team will run in the 2015 McLaren-Honda MP4-30 next season.
Although mid-season testing away from officially sanctioned test sessions is strictly verboten, this particular film session undertaken at Silverstone was apparently allowed under publicity regulations that would permit the team to run the car for no more than 100 kilometers (62 miles). The car was wearing demonstration tires and piloted not by Button, Magnussen or official test driver Stoffel Vandoorne of Belgium, but by backup driver Oliver Turvey, an up-and-coming driver with GP2 and Le Mans class wins under his belt.
The Woking outfit has yet to make an official announcement as to its driver lineup for next season, with Fernando Alonso all but officially confirmed to be making the switch back to McLaren (for which he briefly drove in 2007). The big question mark hangs over whether the team will retain the experienced Button, the aspiring Magnussen or another driver entirely – like Vandoorne or Turvey – to race alongside the two-time world champion. Rumors have linked Carlos Sainz, Jr. (the recently crowned Formula Renault champion and son of the former rally champion) to the team, most likely in a test-driver role.
This filming session marks the official return of Honda to grand prix racing for the first time since it shut down its works team at the end of 2008. It also rekindles a remarkably successful partnership between McLaren and Honda that saw the pair take six world championships during the Ayrton Senna era in the late 1980s and early '90s.