Former F1 World Champion Nigel Mansell on Button, Hamilton, Schumacher and the "most open" of racing seasons.

Mansell spoke to Andrew Marr ahead of the Bahrain Grand Prix, the first race of the 2010 season, and the first race to see 2009 World Champion Jensen Button alongisde 2008 World Champion Lewis Hamilton at McLaren, as well as the return of seven-time champion Michael Schumacher.