The game, which had been due to get under way at 1630, was delayed after hundreds of supporters got into the stadium and on to the pitch, but no revised kick-off time was given by the Premier League.

The Premier League said on its live blog: “The safety of everyone at Old Trafford is paramount. At present there is no revised kick-off time. We will update accordingly.”

Flares were let off by protestors inside the ground, where corner flags were held aloft and one supporter was seen throwing a tripod from the interview zone.

Former United defender Gary Neville told Sky Sports News: “There’s huge discontent. They’re basically saying enough is enough.

“The Glazer family have been resilient and stubborn for many years. I think they’re struggling for many, many years to meet the financial demands this club needs and have done for some time.

“This stadium, if you go behind the scenes, is rusty and rotting. The training ground is probably not even in the top five in this country.

“They haven’t got to a Champions League semi-final for 10 years and haven’t won the league for eight. The land around the ground is undeveloped, dormant and derelict when every other club seems to be developing their facilities and their fan experiences.

“The Glazer family are struggling to meet the financial requirements and the fans are saying the time is up.

“They’re going to make a fortune if they sell this football club. If they were to put it up for sale now I think the time would be right and it’d be the honourable thing to do.”

The PA news agency understands a meeting is under way to establish what happened and the impact on the game, with the pitch damaged by the protestors and Covid-19 protocols to consider.

Fans congregated from around 1pm outside the trinity statue on the Old Trafford forecourt as another group took their protests to the Lowry hotel, where the United team were staying ahead of the game.

Hundreds outside Old Trafford became thousands by the time the protest got under way at 2pm, when two firecrackers were let off and fans began to march towards the Munich Tunnel.

Red fences put in front of the East Stand did not last long, being quickly toppled as stewards were overawed and chanting supporters made their way towards the tunnel.

Footage soon emerged of hundreds of fans on the pitch, with a bunch exiting by jumping down to the nearby canal paths and others running out through the main gates at around 2.30pm.

An hour later another small batch of protestors were seen leaving the stadium. There was no sign of the teams at the ground but the line-ups were announced by the Premier League at 3.30pm.

One of the fans who made it on to the pitch, who gave his name only as Ryan, told the PA news agency: “The protest went better than expected.

“The whole idea of the protest was to cause disruption and I believe that’s what’s been achieved. The atmosphere was unreal, I myself have spent my life idolising this club and to watch how the Glazers have used the club has angered and disappointed me.

“The scenes on the pitch were unreal, we achieved what we needed to and took it further by making it on to the pitch. Do I agree with causing damage? Absolutely not, but what do Manchester United really expect, they have been told for years.”

Another supporter Elliot Brady, 23, told PA: “Best protest you will see at any ground and makes me proud to be a part of it.

“Yeah, we made it on to the pitch, made me feel honoured to be there. Glazers have to sell and return the club back to the fans.”