Unite has accused TfL of entering talks in “bad faith” and announced that engineers vital to the running of Croydon Tramlink will go on strike over pay this month.

The workers are set to strike from 8pm Sunday, May 5, until 6am on Thursday, May 9.

Around 60 tram, stores and infrastructure engineers are angry and claim that their colleagues on the London Underground, who require the same qualifications and perform the same roles, are paid up to £10,000 more a year.

Strike action in March was postponed allowing for talks with TfL but the negotiations failed because Unite claims TfL "refused to be transparent about the process it was using to identify pay disparities and broke its word on how they would be resolved".

Unite general secretary Sharon Graham said: “It is outrageous that TfL somehow thinks it is acceptable to be systemically underpaying highly skilled workers who are essential to keep the tram system functioning.

“TfL was negotiating in bad faith by breaking its promises and withholding information.

“Unite’s patience has run out with TfL’s disgraceful double-dealing and lack of transparency.

“Our members will now be embarking on strike action, and they will have the complete support of their union Unite behind them.”

TfL has admitted five Tramlink engineering roles have pay differences and claims that other roles either do not, or that they are too negligible to be considered.

While Unite disagreed, the union was willing to continue talks if TfL "was transparent", which Unite claims has not happened.

It also claims that TfL backed out on the initial conditions of the talks, which was that if pay disparities were identified a plan would be put in place to bring the impacted roles up to London Underground levels of pay.

Unite says TfL refuses to do this for the five roles it has identified.

The strikes will disrupt Croydon Tramlink services and badly impact London’s transport network south of the river.

Unite regional officer Bruce Swann said: “TfL is entirely responsible for the disruption that will be caused to passengers.

“If TfL had stuck to its word and engaged openly and honestly, the Tramlink engineers would not be forced to take strike action.

“TfL has left these issues to fester for years and the strikes will continue until it resolves them to our members’ satisfaction.”

The dispute also centres on the fact that the engineers are on office worker contracts despite their technical roles.

Unite says this has badly affected the workers’ pay and prevented them from collectively negotiating pay.

After more than five years of negotiations, TfL agreed in 2024 to change the contracts, but there have been "no outcomes from this promise".

A spokesperson for TfL said: “We would never enter conversations in bad faith, and have been open and honest throughout the process.

"We have agreed to work with union colleagues to identify equivalent roles in London Underground, assess any disparity in overall benefits packages, and where agreed take action where appropriate.

"This will take time and we have asked that this strike action be suspended to allow this to happen."

“We remain committed to continued dialogue to reach a conclusion and ask the union to suspend this action, which will only cause unnecessary inconvenience for our customers.”