Henri Toivonen's 1985 RAC Rally-winning Lancia Delta S4 to be sold

The car, which is being auctioned by Sotheby's in its London Olympia sale on Thursday, was also used as a spare car early in 1986 for the Monte Carlo and Swedish Rallies.

The Lancia is available as immaculately restored to original specification.

Just 28 Delta S4s were built in period alongside the 200 road-going versions required for homologation into Group B and this example is one of only four to win a round of the World Rally Championship.

The Delta S4 has a guide price of £725,000-£800,000.

The Lancia Delta project was shelved in 1986 following the accident in Corsica that took the lives of Toivonen and his co-driver Sergio Cresto, before the Group B category as a whole was banned at the end of the season.

Chassis 202 has been used sparingly over the last decade and was driven by Henri's younger brother Harri in a demonstration during the 2016 Rally Finland to mark the 30th anniversary of his brother's death.

At the same action, two Group C sports cars are expected to sell for more than a million pounds each.

A 1989 Jaguar XJR-11, chassis 590, scored three podiums during '90 with Andy Wallace and Jan Lammers and has more recently been raced in Group C events.

With a guide price of up to £1.5m, the ex-Le Mans Porsche 962 chassis 159 will be one of the most expensive lots in the auction.

It was run to 13th at Le Mans in 1990 by the Japanese Trust Racing Team and later went to the US before spending the last seven years in a private collection in Switzerland.