Almost 1,000 bus drivers in London are to stage a series of strikes over pay.
Members of Unite employed by Abellio in south and west London will take 10 days of action in the run-up to Christmas.
The union said the company had not made an offer on pay even though an increase is due in January.
The workers will strike on November 22, 25, and 26 and on December 1, 2, 3, 9, 10, 16 and 17.
Unite general secretary Sharon Graham said: “Abellio is a vastly wealthy multinational company that could and should be paying its workers a fair pay increase.
“With workers struggling to cope with rampant inflation, Abellio's failure to even enter into meaningful pay talks is cold-hearted and callous.
“Unite is now entirely focused on defending and enhancing the jobs, pay and conditions of its members and the bus drivers at Abellio will be receiving the union's complete support.”
The bus drivers are based at garages in Battersea, Beddington, Hayes, Southall, Twickenham and Walworth.
Abellio has been approached for comment.
It comes as Tube workers strike on Thursday in latest walkout to hit London.
All Underground lines were suspended or part suspended, causing commuter chaos, as RMT and Unite union members walked off the job for a sixth time this year.
RMT union claimed last minute talks with Transport for London (TfL) fell through on Tuesday, after they demanded pension and job security with up to 600 station jobs on the line.
A number of bus driver strikes have already caused travel misery in the capital this year.
Drivers in west and south-west London striked over August bank holiday weekend, affecting some routes which served Notting Hill Carnival.
Unite union members working at London United garages, which operates a bus franchise in the capital, took industrial action on August 28 and 29, affecting 63 routes.
Bus drivers also joined London Underground and Overground workers on their strike on August 19.
Unite union bus drivers were striking over a pay offer which the union says is a pay cut when considering the current rates of inflation.
