Manchester United’s Premier League clash against Liverpool was called off after fans broke into Old Trafford in protest against the Glazer family, with police launching an investigation after an officer was left needing emergency hospital treatment.

Around 100 supporters broke into the stadium and invaded the pitch during the demonstration, forcing some United staff to lock themselves in rooms.

Outside the ground, bottles and barriers were thrown at police officers and horses. Two officers were injured, with one “attacked with a bottle and sustaining a significant slash wound to his face, requiring emergency hospital treatment”, Greater Manchester Police said.

GMP assistant chief constable Russ Jackson said it was clear many demonstrators had no intention of protesting peacefully as he condemned their “reckless and dangerous” behaviour.

The Red Devils were among 12 clubs that last month signed up for the breakaway European Super League, which collapsed within 48 hours due to huge, unrelenting pressure.

Those plans brought anger against the already despised Glazer family to a new level, with fans congregating at both Old Trafford and the Lowry, the team hotel in the city centre, to demand change ahead of Sunday’s clash with Liverpool.

Police said that by late afternoon around 200 protesters had gathered outside the Lowry and over 1,000 at the stadium.

GMP said in a statement: “Protesters outside Old Trafford became especially aggressive and antagonistic towards police before a group of about 100 forced entry to the ground, with some United staff having to lock themselves in rooms.

“Those in the stadium were evicted by officers, but outside on the forecourt hostility grew, with bottles and barriers being thrown at officers and horses. Two officers have been injured with one officer being attacked with a bottle and sustaining a significant slash wound to his face, requiring emergency hospital treatment.”

There was an initial unspecified delay to the scheduled 1630 kick-off before confirmation came through from United at 1735 that the match had been postponed “due to safety and security considerations around the protest”.

A club statement read: “Our fans are passionate about Manchester United, and we completely acknowledge the right to free expression and peaceful protest.

“However, we regret the disruption to the team and actions which put other fans, staff, and the police in danger.

“We thank the police for their support and will assist them in any subsequent investigations.”

The Premier League said it understood the fans’ “strength of feeling”, but condemned “all acts of violence, criminal damage and trespass, especially given the associated Covid-19 breaches”.

It added: “Fans have many channels by which to make their views known, but the actions of a minority seen today have no justification.

“We sympathise with the police and stewards who had to deal with a dangerous situation that should have no place in football. The rearrangement of the fixture will be communicated in due course.”

Liverpool, another founding member of the Super League, said they were in “full agreement” with the postponement.

That postponement also denied Manchester City the chance to be crowned champions on Sunday. Defeat for United would have sealed the title for City.

Fans congregated on the Old Trafford forecourt an hour before the protest got under way at 1400, while another group headed to the Lowry.

The hundreds outside the ground had swelled considerably in number by the time the protest started, with two firecrackers let off as protesters began to march towards the Munich Tunnel with green and yellow smoke filling the air.

Red fences put in front of the East Stand did not last long as the handful of stewards were swiftly overcome and barriers toppled.

Footage soon emerged of hundreds of fans breaking into the stadium and on to the pitch, with corner flags held aloft and one supporter seen throwing a tripod from the pitchside interview zone.

A number of the protesters left the ground around 1430, exiting the stadium complex by jumping down to the nearby canal paths or running out through the main gates.

Another group is understood to have got into the stadium shortly after, with a small batch of protesters seen leaving around 1530.

Assistant chief constable Jackson said: “The actions of those today required us to take officers from front-line policing and call in support from neighbouring forces to prevent the disorder getting worse. At different points, bottles and barriers were thrown, officers assaulted and people scaled the stadium structure creating risk for themselves and officers.

“We have launched an investigation and we will be working closely alongside partners to ensure we establish the full circumstances surrounding today’s events and prosecute those responsible.”

Stu Berry, chairman of Greater Manchester Police Federation, added: “We witnessed appalling scenes this afternoon – police officers are not punchbags for people protesting for their cause.

“At the end of their shifts, hard-working police officers should be able to go home to their families in one piece. Not be rushed to hospital.”

Andy Burnham, mayor of Greater Manchester, said on Twitter: “It is important to make clear that the majority of supporters made their protest peacefully today. However, there is no excuse for the actions of a minority who injured police officers and endangered the safety of others.

“This could be an important moment to change football for the better. We should all condemn violence of any kind and keep the focus on the behaviour of those at the top of the game.”

Manchester United Supporters Trust wants the Government to act to prevent single private shareholders holding majority ownerships in football clubs.

It said in a statement: “On the back of the indefensible ESL proposals, and an ‘apology’ from the Glazers which we do not accept, we need to give fans a meaningful share in the ownership of United and a meaningful voice in how it is run.

“The Government now needs to act. That has to mean a process which results in fans having the opportunity to buy shares in their club and more to the point no single private shareholder holding a majority ownership of our football clubs which allows them to abuse that ownership.”