The leader of the country's second biggest trade union Amicus has conceded defeat leaving a relatively unknown left-winger to take charge.

Sir Ken Jackson has decided not to contest his dramatic defeat in the leadership ballot and will step down from his job at the end of the year.

Sir Ken reached retirement age this year

His decision marks another disappointment for the government in its increasingly fractious relationship with the unions.

Sir Ken had initially refused to accept defeat in the election for the leadership of the AEEU section of the Amicus super-union, even though his opponent, Derek Simpson, won on four recounts.

Downing Street has steadfastly refused to comment on the troubled election.

Union opposition

But Sir Ken's departure will be a blow for the government, said BBC political correspondent Reeta Chakrabarti.

It has lost a loyal ally at a time of need - other union leaders are becoming increasingly outspoken in their criticism of plans for private sector involvement in the running of public services, she said.

Mr Simpson, a former Communist, said on Saturday that union members had voted for a change because they felt their leaders were "autocratic and had lost touch with them".

He added it would now be unwise of the government to ignore the views of a union with more than a million members, particularly as it was a major contributor of Labour party funds.

Mr Simpson was declared the winner after a fourth count on Thursday when he polled 89,521 votes to Sir Ken's 89,115.

Sir Ken reached the normal retirement age of 65 this year but wanted to stay in his post until the end of 2004 to oversee the merger between the AEEU, and the MSF.

The two unions linked up earlier this year to form Amicus, which has a million members, mainly in manufacturing.