Three bus strikes planned for February threaten transport misery for millions.
The first walk-out by drivers takes place on Thursday, with two more slated to go ahead on February 13 and February 16.
Unions and bosses at Transport for London (TfL) have fallen out over pay for drivers, which can vary by up to £3 an hour depending on the bus operating company.
Unions are demanding pay parity across the 18 firms which run routes in the capital city. TfL claims it would cost £100m and cause fare rises.
Unite Union officer Wayne King said: "We urge London's bus operators to see sense and collectively engage in talks to give London's bus workers a fair deal."
TfL's director of buses, Mike Weston, said: "It would be much better if the leadership of Unite actually worked with the bus companies to ensure that it remains that way rather than disrupting bus passengers."