Nine London MPs have backed the strike
Hundreds of Tube cleaners are to launch further strike action in the ongoing row over pay and conditions.
More than 700 cleaners employed by four sub-contractors want hourly rates raised from £5.50 to £7.20 plus improved holidays and pensions.
The 48-hour industrial action by members of the Rail Maritime and Transport (RMT) Union follows a 24-hour walk-out last week.
Transport for London (TfL) called the strike action "completely unnecessary".
Early day motion
"We have already reassured all interested parties, notably the trade unions, that we are taking this commitment forward," said a TfL spokesman.
But RMT leader Bob Crow insisted that negotiations had barely begun.
"London mayor Boris Johnson has stated that all temporary and contracted GLA staff should be paid at least the living wage as the contracts come up for renewal and Tubelines has indicated that it would be willing to enter negotiations on the issue," he said.
"However, three cleaning companies with contracts with Metronet are currently in talks with TfL right now and paying the London living wage isn't even on the agenda."
Last month, 24 London MPs backed an early day motion tabled by Hayes and Harlington MP John McDonnell supporting the cleaners.