Tube workers were poised to launch a massive 48-hour walkout yesterday after slippery London Mayor Boris Johnson refused talks with rail union leaders.

The RMT's Bob Crow and TSSA general secretary Manuel Cortes travelled to City Hall in a bid to persuade Mr Johnson to hold last ditch talks.

The Tory mayor has refused to speak to union leaders since taking office in 2008 and the pair found he had fled once again.

Determined Mr Crow then called LBC radio's Ask Boris phone-in on his mobile from outside City Hall.

Speaking to Mr Johnson live on air, the union leader appealed for him to at least listen to safety concerns over his plan to close ticket offices and slash 750 jobs.

He said: "We are not here to score points - all we want is an opportunity to negotiate about the Tube.

"We are asking you to listen to our point of view. We would love to call the strike off."

The mayor bumbled back: "It's good of you to call in, Bob."

He then launched a charm offensive on listeners, insisting he had respect for workers who "run the greatest Tube system in the world" but claimed that job losses are "inevitable."

The bizarre turn of events were the union's latest efforts to end the dispute after appealing for talks at a joint press conference at the TUC's Congress House on Monday.

But with Mr Johnson remaining elusive, the RMT made clear to Londoners that the strike was on from 9pm.

Mr Crow said: "We have been to City Hall, made ourselves available at any location of his choosing and he has point-blank refused to meet with us.

"As a result, the strike goes ahead."

Austerity-loving Prime Minister David Cameron waded into the dispute through his spokesman, who said the millionaire PM thinks Mr Crow is "plain wrong" to cause "misery" for Londoners.

Labour transport spokeswoman Mary Creagh said: "It is disappointing that the mayor and Transport for London have not reached a resolution with the unions ahead of this strike."