Tributes paid to Marco Simoncelli

Leading figures from the worlds of both motorcycle and car racing have been paying tribute to Marco Simoncelli, who was killed today in MotoGP's Malaysian Grand Prix.

The 24-year-old Italian, who had been the sensation of the 2011 season, fell on lap two of the Sepang race and was struck by following riders. He was pronounced dead at the circuit's medical centre shortly afterwards.