RMT members are currently being balloted over pay

Ken Livingstone had wanted Tube trains to run until 0100 on Friday and Saturday nights but he claimed the unions were demanding too much money.

Rail Maritime and Transport (RMT) officials said any pay rise should not be linked with later running Tubes.

An Aslef spokesman said the problem was not the Tube drivers and blamed London Underground (LU) negotiators.

The spokesman said: "We are taking no action and we are quite prepared to negotiate."

Conditional offer

London organiser for Aslef Steve Grant added that: "Nothing has been negotiated, and there is therefore no deal to put to anyone."

Currently thousands of RMT members are being balloted for strike action over claims a 4% pay rise has been withheld from last April.

Speaking at his weekly news conference Mr Livingstone announced that the cost of meeting the unions' claims was "prohibitive" and he had decided to suspend introduction of later running trains.

The mayor said it was a fair deal which would not be increased.

An RMT spokesman said: "It is London Underground that has linked the pay deal with an agreement on late running Tubes.

"We are asking for the two issues to be dealt with separately and not that one is conditional on the other.