Risil, on 22 Apr 2020 - 18:48, said:
Because F1 was very anal about driver numbers in those days and you couldn't be car 1 unless you'd won the championship the year before. Alain Prost was 1993 world champion and retired so Williams got 0 and 2.
Interestingly, provided you find this kind of thing interesting, something similar happened in Indycar when Jacques Villeneuve departed with the championship in 1995. His team got the number 1 for 1996 so JV's replacement Raul Boesel ran it instead.
Hill was #0 in 1993 as well, with Mansell having left F1 as the reigning champion. Had Williams run #1, it would have been for Prost and then Senna. I suspect neither of them wanted to, but also didn't like #0. Funnily enough, it became associated with Damon in a quirky way, somewhat like Mansell and "Red 5". It is strange to see Nigel in "Red 2" here.
Edited to add: Ronnie Peterson used #1 in 1974 after Jackie Stewart retired, so there was a precedent for the reigning constructors champions using #1 for their lead driver if the actual WDC had retired or left F1 for some reason.
Edited again: John Watson drove with #1 in the 1985 European Grand Prix at Brands Hatch, standing in for the WDC Niki Lauda who had hurt his wrist in a crash at Spa.
Edited by garoidb, 22 April 2020 - 20:10.