A senior official of the biggest rail workers’ union has been elected as the new general secretary.

Mick Lynch, 58, beat three other candidates to lead the Rail, Maritime and Transport union, where he has been assistant general secretary for a number of years.

He replaces Mick Cash, who said he was retiring after blaming a “campaign of harassment” against him by factional groups within the union.

Mr Lynch, who has been in the union for 30 years, was blacklisted by the construction industry earlier in his career for trade union activities.

The election was triggered after Mr Cash announced last October that he was standing down, citing a campaign of bullying and abuse within the union which he said made it impossible for him to do his job.

Mr Cash had been elected after Bob Crow died suddenly in 2014.

Mr Lynch said: “I am greatly honoured to have been elected by the RMT’s members as general secretary.

“I will maximise the unity of our great organisation, bringing together every sector and grade to build our union’s membership, influence and power. We will grow our union in every workplace as a strong and dynamic force.

Our message to the employers and the politicians is that RMT stands ready to campaign and fight against pay freezes, cuts to safety and conditions

“Our message to the employers and the politicians is that RMT stands ready to campaign and fight against pay freezes, cuts to safety and conditions.

“We call on the rest of the Labour movement to stand strong and mobilise against any new age of austerity which makes working people pay for the Covid crisis.”

Mr Cash said: “I want to congratulate Mick Lynch on his victory and I know that with Mick now elected as RMT general secretary that the union is in safe hands.

“There will be huge challenges in the months ahead ‎as employers launch assaults on jobs, pay and pensions using the Covid pandemic as an excuse.

“It is crucial that the whole union now unites behind Mick Lynch as general secretary and gives him the support that he will need as RMT focuses on delivering ‎for our members in what we know will be tough days ahead.”