Boris Johnson has been urged to clarify whether he signalled his support for the European Super League (ESL) in a meeting with Manchester United's executive vice-chairman Ed Woodward just days before the controversial plan was made public.
Mr Woodward met with No 10 officials at Downing Street to discuss the return of fans to stadiums as coronavirus restrictions are eased.
But he reportedly chatted with the prime minister after bumping into each other in a corridor.
Days later the ESL plan was made public, with United one of six Premier League clubs signing up.
Following a fierce backlash from fans, football authorities and the Government - including opposition from Prime Minister Johnson - several clubs pulled out and the plans were quickly dropped.
But the Sunday Times reported that sources have alleged Mr Woodward left his April 14 meeting with the Prime Minister under the impression the plan had been endorsed.
Government sources have reportedly strenuously denied the suggestion, saying the PM had not been in the meeting and it was a chance encounter in a Downing Street corridor.
Mr Woodward was introduced to the Prime Minister following the meeting with No 10 chief of staff Dan Rosenfield on Wednesday last week.
But Labour have demanded answers from prime minister, saying he should clarify what if anything was 'promised to Manchester United about a European Super League'.
Shadow Secretary of State for Culture, Media and Sport Jo Stevens has written to Cabinet Secretary Simon Case, demanding details of the encounter and who was present..
Stevens said: "Yet again, Johnson’s integrity and honesty are in question. The public has a right to know what exactly was promised to Manchester United by both officials and the prime minister.
“If Johnson gave the European Super League his backing and then publicly turned on the plan then the British people deserve a full, clear and immediate explanation and apology.”
Mr Johnson tweeted his views hours after the plan was unveiled.
He wrote: “Plans for a European Super League would be very damaging for football and we support football authorities in taking action.
"They would strike at the heart of the domestic game, and will concern fans across the country.
“The clubs involved must answer to their fans and the wider footballing community before taking any further steps.”
United and the other Premier League clubs later withdrew from the ESL.
Following the fiasco Manchester United announced Mr Woodward would leave by the end of the year.
