Theatre owner Sir Cameron Mackintosh has criticised Prime Minister Boris Johnson after football fans scaled the walls of one of his theatres before England’s game against Italy.

Sir Cameron, who looks after a number of West End venues, said repair costs to the Wyndham’s Theatre, just off Leicester Square in central London, are thought to be in the “tens of thousands”.

In a letter to Mr Johnson, he wrote: “As was widely reported and condemned on social media, at approximately 5pm [on 11 July], around 50 people broke through fencing at Wyndham’s Theatre and climbed on to the delicate canopy of this 19th century, Grade II listed building in the heart of the West End.

“Despite similar incidents after the semi-final, the police appeared insufficiently resourced to deal with this vandalism and the danger posed to the trespassers, and it was only later that riot police finally arrived.

“No doubt, had England won the match – which we were all rooting for – the situation would have greatly worsened later in the evening. Significant damage was inflicted on the theatre, with repairs estimated in the tens of thousands, and the incident could easily have resulted in serious injury or fatality.”

Sir Cameron called the scenes a “grim metaphor” for how he feels they have been treated during the pandemic, saying the theatre industry has been left to “fend for itself”.

He added that theatres have been denied direct financial help and that the isolation rules are “unworkable”.

The impresario – who is behind London iterations of Hamilton and Mary Poppins – goes on to ask the prime minister why theatres have only been allowed to open with a capacity of 50% or 1,000 and comply with “extensive” mitigations, yet “tens of thousands of people” were allowed to head to central London with “seemingly little to no crowd management”.

The theatre in question is due to open on 7 August with a production of Leopoldstadt.

Speaking to The Times, Sir Cameron said that COVID “caveats are causing us chaos”, revealing that during its first day of rehearsals for Hamilton this week, 15 cast members had to be sent home due to track and trace, while re-openings of Hairspray and Prince Of Egypt had to be postponed.

Football fans were gathered across central London on Sunday ahead of England’s game at Wembley Stadium, with some spotted scaling buses, cinemas and restaurants, as well as letting off flares and fireworks in Leicester Square.

This was despite efforts to enforce social distancing across the capital, as thousands arrived for the game.

Sunday’s match, which England lost on penalties to Italy, had an attendance of more than 60,000 and was part of the government’s pilot events scheme – despite theatres having their audiences capped.

In response to Sir Cameron’s criticisms, the Home Office directed Sky News to Priti Patel’s tweet from Monday, which said: “A huge thank you to every police officer who’s been working in Wembley & across the country throughout #EURO2020.

“You’re a credit to policing in this country & should be incredibly proud.

“I condemn the violent minority who assaulted you last night – these thugs aren’t true fans.”