LONDON Underground will grind to a halt tonight as almost 20,000 Tube workers walk out on strike.

The Tube’s four unions, blue-collar RMT, white-collar TSSA, drivers’ union Aslef and general union Unite, will lead 24-hour strike action from 9.30pm in opposition to Transport for London (TfL) plans to impose all-night work.

Last-ditch talks were convened with conciliation service Acas at 1pm yesterday, but a few hours later Aslef lead negotiator Finn Brennan confirmed that the strike was on.

“Sadly, we were not able to make sufficient progress to avoid industrial action and it is clear that we cannot do so at this late stage,” he said.

“The responsibility for this strike and the disruption that it will cause rests squarely with London Underground management. “They squandered the window of opportunity to resolve this dispute by refusing to move their position in the slightest for three months and then demanding that all four trade unions accept an offer in one afternoon.”

London Underground management said on Monday that it had not withdrawn a deal aimed at settling the dispute.

But Aslef obtained a management “question and answer” document stating categorically that the offer was “conditional on the trade unions suspending all industrial action” and “it means that this offer is time-bound and if the conditions are not accepted by 18.30 today the offer will be withdrawn.”

Mr Brennan said that, despite claims by the Transport Commissioner that the dispute was political, it was a solely industrial matter.

“Money has never been the key issue in this dispute — ensuring that change is negotiated rather than imposed and introduced in a fair way has,” he said.

RMT general secretary Mick Cash said: “Despite strenuous efforts by union negotiators to press London Underground to address the issues of fairness, safety, work-life balance and equality at the heart of this dispute, they have come up with nothing in the talks this afternoon.”

• In a separate dispute, thousands of members of RMT working for First Great Western will strike for 48 hours from 6.30pm today over jobs on, and the maintenance of, Hitachi’s replacement for the famous Intercity 125 trains, built between 1975 and 1982. Services between London and Wales and the West Country will be hit.