The Didcot-based team missed the 15 November deadline for applications to the sport's governing body, because of 'an administrative error', and Benetton-Ford and Minardi are so far unwilling to sanction a waiver.
At the time the 'error' became apparent, Bernie Ecclestone, the president of the Formula One Constructors' Association and vice-president of Fisa, the man who effectively runs the show, insisted Williams had applied through Foca, which was permissible, and that there was no question about their participation.
That remains the case. No one doubts Williams will be defending their title this year.
Winners, however, tend to make enemies and Williams' resistance to a series of proposals for artificially containing their expected supremacy has prompted this retaliatory stance. A long-running legal wrangle between Elf, Williams' fuel suppliers, and Fisa, has also served to galvanise the opposition.
Williams argue - with justification - that weight handicaps, pace cars when a team has a 12- second advantage and like measures would be ludicrious. Introducing such farcical regulations would further devalue a formula in desperate need of credibility after the unsavoury squabbles of the recent past.
It has lost its world champion, Nigel Mansell, and is still in danger of losing a former champion, Ayrton Senna, said to be planning a season's sabbatical before taking up an option on a three-year contract with Ferrari. That it could lose its champion team - along with their drivers, Alain Prost and Damon Hill - is unthinkable.
Yet now the sport has to go through the charade of finding a compromise solution to this 'special case'. Only then can Williams's cars be added to the 26 already accepted for the championship, which begins in South Africa, on 14 March.
Benetton-Ford confirmed yesterday that they are opposed to Williams' readmission. Their managing director, Flavio Briatore, frustrated by Williams' rejection of rule changes, has seized on the opportunity to beat his opposite number, Frank Williams, with his own stick and put pressure on him to support a revision of Foca's voting system, which at present requires unanimous support for changes in regulations. The Italian team, Minardi, admitted they had also declined to support Williams' readmission.
Frank Williams said last night: 'Our entry was received by the Fisa on 16 November. Fisa required us to seek the acceptance of the entry by the unanimous agreement of all the other teams.'
Team list, Sport in Short, page 31