Rail and Tube workers are to planning to stage strikes over the May Bank Holiday weekend in separate disputes over pay, jobs and conditions.
Members of the Rail, Maritime and Transport union (RMT) are involved in rows with Heathrow Express and London Underground which will lead to industrial action. Words and pictures: PA
Union members at Heathrow Express will walk out for 24 hours from 3am on Friday, and again from the same time on Bank Holiday Monday in protest at plans to make £6 million of savings, which the RMT said threatened more than 200 jobs.
Acting general secretary Mick Cash said there was growing demand for the rail service linking Heathrow airport with Central London, arguing that it made no sense to make cuts.
Heathrow Express said it planned to run a normal service despite the strikes.
Meanwhile, power control staff on London Underground will strike for three days from Saturday in a dispute over pay and conditions.
The RMT said it was opposing plans to outsource work.
Richard Jones, London Underground's head of command and control, said: "Unite, TSSA and RMT have raised a number of issues with us around workplace and terms and conditions relating to staff in our power control team, all of which are either being addressed or we are happy to discuss.
"We would urge all unions involved in this dispute to continue discussions to resolve this matter without the threat of industrial action."
Keith Greenfield, managing director of Heathrow Express, said: "The RMT's misguided decision to strike again ignores the reality that Heathrow Express needs to save £6 million of cost over the next five years in order to secure its future and jobs for its people.
"Burying one's head in the sand does not alter the fact we need to implement changes to secure our future. We would of course prefer to do this with the agreement of the trade unions to ensure the best outcome for everyone, including RMT members."