Mick Lynch, one of the UK's most influential union leaders in recent history, has announced he is retiring.
Mr Lynch is stepping down from the helm of the RMT (Rail Maritime and Transport Workers) union aged 63.
He has served as general secretary since 2021.
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Under his leadership, the union waged years of strike action over pay, job cuts and working conditions before accepting a deal with the new Labour government this summer.
The rail strikes by RMT members were part of the wave of industrial action that meant 2022 had the highest number of strike days since 1989.
Walkouts began in June 2022 and did not officially conclude until September 2024.
Mr Lynch became known for his frequent television appearances explaining and defending strike action.
"It has been a privilege to serve this union for over 30 years in all capacities, but now it is time for change," Mr Lynch said.
"This union has been through a lot of struggles in recent years, and I believe that it has only made it stronger despite all the odds," he added.
He will remain in post until a successor is appointed in May, the RMT said.
No reason was given for his departure but Mr Lynch said there was a need for change and new workers to fight.
"There has never been a more urgent need for a strong union for all transport and energy workers of all grades, but we can only maintain and build a robust organisation for these workers if there is renewal and change," he said.
"RMT will always need a new generation of workers to take up the fight for its members and for a fairer society for all."
A career of organising
Mr Lynch first joined the RMT in 1993 after he began working for Eurostar.
Before being elected secretary general at the top of the organisation, he worked as the assistant general secretary for two terms and on the union's national executive committee, also for two terms.
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As a qualified electrician, Mr Lynch helped set up the Electrical and Plumbing Industries Union (EPIU) in 1988, before working for Eurostar and joining the RMT.
He had worked in construction and was blacklisted for joining a union.
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