RAIL unions have demanded that London Mayor Boris Johnson stop posturing about pay and negotiate seriously over his plan to impose night working on Tube drivers.

The call came as London Underground shut down yesterday after four unions walked out for the second time in a month as part of a long-running dispute over plans to launch a new all-night service next month.

The mayor has long refused to negotiate with unions directly but yesterday the RMT and TSSA said the time had come for him to meet them face-to-face in a bid to end the dispute.

RMT general secretary Mick Cash said: “The night Tube is his personal project and as chair of Transport for London it is now time for the mayor to reverse his long standing policy of not meeting with the trade unions and to give our negotiators an opportunity to set out the facts to him directly.”

TSSA leader Manuel Cortes added that the mayor “is the man in overall charge and he is the man who is in charge of the overall budget for a service which is now due to start in just five weeks’ time. He holds the key to ending this disruption.

“He should be sitting around the table with all the four unions to agree a way forward which will avoid the need for any further action. We will meet him anywhere, anytime.”

Mr Cortes said the unions were still concerned about safety and staffing levels as well as work-life balance, with over 1,200 staff having to work more weekends under LU’s current plans.

But yesterday Mr Johnson appeared to remain as intransigent as ever, saying he was “not fussed” about the new service starting on time on September 12.

“I am not going to authorise any more money. Most people would recognise that this is a very generous deal,” he said.

Aslef general secretary Mick Whelan said: “Our members have rejected the offer because they are forcing through new rosters without agreement and offer no firm commitments on work-life balance.”