The Unite members action hit 13 routes. A union spokesperson said: "Faced with an increasingly hostile management which is hell bent on driving down the pay, terms and conditions, our members have been left with little option but to take the unusual step of striking... Tower Transit need to get back around the negotiating table and start treating its workforce with respect."
The industrial action is the first strike over the dispute, with a second 24-hour walkout planned for Monday 5 January.
Tower Transit is a relative newcomer to London. It was formed when Transit Systems (a transport group based in Australia) bought up the Atlas Road, Lea Interchange and Westbourne Park garages from FirstLondon (a subsidiary of FirstGroup) in 2013.