EURO MP Mike Hindley is stepping down from his Lancashire South seat at the next election in 1999.
The controversial MEP, recently at the centre of a gagging row in the European Parliament, launched a broadside on the party when he announced his decision at the weekend.
Mr Hindley last week won his battle to refuse to sign a gagging order after winning the support of his colleagues in Brussels.
But the MEP says his decision was made this summer before the row blew up, and was made for personal and political reasons.
In a statement to the Lancashire South constituency party on Saturday, Mr Hindley said that as well as having to commute from his home to Brussels or Strasbourg, the introduction of proportional representation (PR) in Euro elections was a major factor in his decision.
"I think the advent of proportional representation will fundamentally change the nature of an MEP's relationship to the party and the locality in an unhealthy manner."
And he said a PR list system would "extend the undemocratic power of patronage in an already over-centralised Labour Party. "The actual system the party is suggesting, the so-called 'closed list' system, is the most undemocratic version of PR on offer, both for the electors and for the Labour Party itself in its selection process."
But Mr Hindley said he was a supporter of proportional representation, which he said could "break the dominance of the present centre right consensus" in politics. Mr Hindley said he would not be retiring from politics when he stepped down in 1999.
"We are going through profound changes in the political make-up of this country and I intend to play a full, active and constructive role in those changes," he said.
"I shall continue to seek ways to put into practice those ideals which first brought me into politics and membership of the Labour Party," he went on.
"For me those can still be summed up in the commitment of the 1983 General Election manifesto on which I stood, that is bringing about a fundamental and irreversible shift in the balance of wealth and power in favour of working people and their families."
Mr Hindley said he had made his announcement now only because an earlier meeting was cancelled because it clashed with the Princess of Wales' funeral and in no way was it connected with the recent row.
"Those events were concluded with a full and unconditional vindication of my stand for the right to dissent within the party," he said.
Converted for the new archive on 14 July 2000. Some images and formatting may have been lost in the conversion.
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