More than 2,100 bus workers across the capital could walk out on strike amid a row over pay.
The Unite union said on Tuesday it was balloting 300 London Transit staff for strike, meaning a total of 2,100 workers could be poised for industrial action when other ballots are taken into account.
The latest ballot concerns drivers and engineers who are based at Westbourne Park bus garage in Notting Hill.
In addition, around 100 London United engineers based at eight garages providing services for South, Central and West London, have also joined 1,600 London United drivers in balloting over pay.
London United and London Transit are both part of the French state owned RATP Group.
Unite general secretary Sharon Graham said: “RATP is a multi-billion pound company and can more than afford to put forward reasonable pay offers for its London Transit and London United workers.
“It must also properly consult with Unite to ensure that its scheduling agreements are fit for purpose. Unite is offering complete support to our members as they ballot for strike action.”
The London Transit ballot closes on July 31, while the London United engineers ballot closes on August 1. London United drivers will finish balloting on July 22.
Strike action will cause severe disruption to bus services in South, West and Central London, Unite said.
A separate planned bus strike for workers at Abellio was called off in May after a fresh pay offer was made.
The industrial action, which would have seen 40 control room staff based in Battersea and Twickenham walk off the job from May 8, was instead suspended.
The Standard has contacted RATP for comment.
However, it said in a previous statement about bus strikes that it was “extremely disappointed” by any industrial action.
It has said that its pay offers are “competitive and fair” and that it has negotiated with unions to provide good working conditions.
