Talks were due to resume between the RMT and railway bosses on Monday, with the union’s national executive committee considering new strike dates as the Prime Minister backed plans to close ticket offices.

Services began to return to normal after a later start on Sunday due to the latest of three nationwide 24-hour strikes by workers at Network Rail and 13 rail operating companies on Saturday.

Other walkouts could be called at the end of July. An RMT spokesman said the union would “evaluate and look to the next phase of the campaign”.

Speaking ahead of the G7 summit in Germany, Boris Johnson said that to justify the money being spent on the railways, including the £96billion spent on the Rail Investment Plan, “the traveling public and the taxpayer is going to want to see reform and improvement in the way the railroads operate” and there could be no “business as usual”.

He told ITV News: “I can’t responsibly tell them that we’re just going to just carry on business as usual, with the same old ticketing systems that are barely used, or sell a ticket every hour. .”

The Department for Transport rejected claims by the TUC that the government had misled the public about its role in the dispute.

Legal advice obtained by the TUC from QC Michael Ford said the Transport Secretary has ‘very wide powers’ over what can be agreed between rail operators and unions, and ‘very significant contractual power to direct how disputes are handled.

According to Ford’s legal opinion, the contractual provisions binding the railroads mean that they “do not have the freedom to negotiate the issues that gave rise to the current litigation.”

TUC general secretary Frances O’Grady said: “We have always believed that Tory ministers have the power to pull the strings of the rail companies, behind the scenes. And this legal opinion on railway contracts confirms it.

A DfT spokesperson said that did not mean Grant Shapps should get involved in the negotiations, adding: ‘He is required to set the limits of taxpayer support and ultimately sign any deal – not to be involved in negotiating a – and its contracts with operators. allow him to do precisely that.

Johnson’s intervention is likely to stoke tensions between railway unions, employers and the Department for Transport over the refusal to rule out compulsory redundancies resulting from a planned modernization of rail services, including the closure ticket offices.

Drawing on his role as mayor of London, when he fought to close ticket offices at Tube stations, Johnson added the government was doing ‘pretty unbelievable things’ on the railways, pointing to Crossrail and the integrated rail program.

“To justify paying this money, making these commitments. I think travelers and taxpayers will want to see reform and improvement in the way the railways work,” he said.

Shadow Foreign Secretary David Lammy has slammed the government for failing to negotiate – but he also said he was categorically unsupportive of airline workers who also voted to strike for wage demands.

Regarding the rail dispute, Lammy told the BBC: “This government does not negotiate. This government does not support the search for a compromise.

However, when asked if he supported the claims of British Airways check-in and ground staff at Heathrow who voted to strike to reinstate a 10 per cent pay cut, Lammy replied: ‘No, I do not do it. It’s a no. It’s a definite no. »

He criticized Labor MPs who had joined the picket lines. One, Nadia Whittome, announced on Saturday that she would donate part of her salary to the local RMT strike fund.

The first results of strike ballots at another rail union, the TSSA, are expected later this week, which could deepen the dispute and the effects of any coordinated action. TSSA members include controllers and managers who acted as emergency and back-up personnel during RMT walkouts. The union has launched its first ballots at the rail companies serving Birmingham, the host city of next month’s Commonwealth Games, as well as at Network Rail.

Drivers from the Aslef union will, meanwhile, go on strike over wages on Tuesday and Wednesday in trams in Croydon and next Saturday in Greater Anglia.