Nigel Mansell is putting a pair of F1 cars from his personal collection up for auction. Pic: RM Sotheby's

A PAIR of Grand Prix-winning Formula 1 cars from Nigel Mansell’s personal collection are set to be auctioned.

Mansell’s 1989 Ferrari 640 and 1991 Williams FW14, which currently sit in his private museum on the island of Jersey, headline RM Sotheby’s in Monte-Carlo on May 14 during the Monaco Historic Grand Prix.

Both cars have been owned by Mansell since the end of their competition careers, having been gifted them by their respective teams.

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Ferrari 640 Chassis 109. Pic: RM Sotheby’s

The Ferrari 640 is chassis 109, was Mansell primary race chassis for much of the 1989 season including the Australian Grand Prix in Adelaide.

The John Barnard-designed car was the first in Formula 1 history to feature a semi-automatic gearbox, with gears changed electronically by a pair of paddles behind the steering wheel.

Mansell drove this chassis to victory in its first race – also the first race of F1’s 3.5-litre normally aspirated engine era – at the 1989 Brazilian GP and also to the win at the Hungarian GP, one he sealed with a dramatic pass on Ayrton Senna late in the race.

Ferrari 640 Chassis 109. Pic: RM Sotheby’s

The Williams on offer, a passively-suspended FW14 that was the forerunner to the all-conquering FW14B, also featured in several iconic moments from F1 history in Mansell’s hands during the 1991 season.

Chassis 5 debuted at that year’s French GP and helped launch a late challenge for the title against runaway championship leader Senna.

Mansell won three races on the trot in this car, including the British GP where he gave Senna, who’d run out of fuel on the final lap, a lift back to the pits on the car’s sidepod.

Williams FW14 Chassis 5. Pic: RM Sotheby’s

Another win came at the Italian GP, but a win in Portugal memorably went begging when a wheel fell off in pit lane following a pit stop.

The car’s final win came in the Spanish GP, the first run at the Circuit de Catalunya and best remembered for Mansell running wheel-to-wheel with Senna down the long front straight as they battled for the lead in greasy, semi-wet conditions, but a spin while following Senna in the early laps in Japan finally ended his title hopes.

Mansell finished the season classified second in the season-ending Australian GP despite crashing chassis 5 in the dismally wet conditions, an incident with aggravated an existing foot injury and helped prompt officials to red-flag the race to an early conclusion.

Williams FW14 Chassis 5. Pic: RM Sotheby’s

The Ferrari comes complete with its original 3.5-litre V12 engine and semi-automatic gearbox, but the Williams is without its Renault V10.

The Williams is expected to sell for between 1.5-3 million euros (AU$2.24-4.49m) and the Ferrari is tipped to fetch 2.5-5 million euros (AU$3.74-7.48m), per Classic Driver.

The cars are two of five cars that Mansell has contributed to the auction from his collection, with his Reynard Champ Car-based Grand Prix Masters car, a Birkin 7 Sprint and iC Modulo M89 also set to go under the hammer.

Click here to view the auction lots on RM Sotheby’s website.

Will Dale is V8 Sleuth's Head of Content - Digital. He began his media career as a breakfast radio newsreader before joining SPEED TV Australia and FOX SPORTS Australia in 2012 as its Digital Editorial Lead - Motorsport, covering all forms of motorsport both in Australia and internationally. He became part of the V8 Sleuth team in 2018.