Strikes could be held next month

The Rail, Maritime and Transport (RMT) union said up to 6,500 members would be balloted over claims a 4% pay rise has been withheld from last April.

London Underground said once its offer of a three-year above-inflation pay rise was accepted RMT members would be entitled to this year's pay increase.

A strike could be held at the end of next month if staff back the ballot.

Increased productivity

A London Underground spokesman said: "RMT should be putting this...offer to their members, which has already been backed by TSSA union members in a ballot by over 80%.

"We have not refused to pay an increase this year. We have made a very fair three-year offer which has been on the table for a number of months.

"As soon as the offer is accepted, RMT members will be entitled to their pay increase for this year."

RMT general secretary Bob Crow said: "LU has been boasting that our members handled a record-breaking four million passengers on one day last month and that passenger levels are up by 10%.

"If productivity is up by 10% why are they refusing to pay the 4% rise their record-breaking staff should have had last April?"