Reports that Labour may be preparing to drop the manifesto commitment for a referendum on voting reform have sparked a heated internal debate.

The row emerged after a consultation of party members suggested strong resistance to voting reform following the co-ordination of responses to the consultation by campaigners in favour of the status quo.

Labour MPs such as Fraser Kemp and the leader of the GMB union John Edmonds have thrown their weight behind calls to ditch the commitment.

While MPs like Stephen Twigg who is in favour of a proportional system claim the prime minister backs them.

So far Mr Blair has remained neutral saying only that he is not yet convinced of the need for change, but he has not ruled it out.

The cabinet remains split on the issue but if voting reform is dropped from Labour's agenda it may threaten future co-opeartion between the party and the Liberal Democrats.

Consultation leaked

Labour supporters of the present first-past-the-post system were thought to be behind the leaking of the preliminary internal consultation results.

Responses to the consultation exercise appeared to show massive opposition to scrapping the first-past-the-post system for Westminster elections, according to a number of reports.

One said about 1,250 submissions had been received opposing reform compared with only 350 in favour of change.

BBC News Online has also learned that just a few days before Christmas, first-past-the-post campaigners bulk-delivered what one described as "hundreds" of responses to Labour's Millbank Tower headquarters.

The consultation period formally closed on 31 December.

'Drop the promise'

Leading member of the First Past The Post Campaign Fraser Kemp suggested Labour's manifesto commitment to a referendum on voting reform could now be dropped.

The Houghton and Washington East MP told the BBC: "I don't think it's necessarily a commitment that lasts forever. I think there's a reasonable chance that we wouldn't go into the next election with this manifesto commitment."

While union leader John Edmonds agreed saying: "I don't think there'll be a manifesto commitment honoured [on it] in this parliament and I don't think it will be in the next manifesto."

But Mr Twigg dismissed the idea: "Labour's pledge to the electorate to hold a referendum on voting reform will be carried forward in the next manifesto and will be enacted early in the life of the new parliament."

Mr Twigg, chairman of the Make Votes Count group in Labour, also warned anti-voting reform MPs against using the consultation exercise to divide the party on the issue.

'Bizarre' not to reform

Chairman of the Liberal Democrat Parliamentary party Malcolm Bruce also warned it would be unacceptable if Prime Minister Tony Blair used the results as justification for retaining first-past-the-post.

Mr Bruce argued that it would be inconsistent for a government that has carried out so much constitutional reform to leave the voting system unchanged.

"If constitutional reform has any value at all, it's about improving the quality of government, and that's the reason for wanting electoral reform," he said.

Threat to Lib-Labbery

Although the prime minister is known to be keen to forge closer links with the Liberal Democrats, party leader Charles Kennedy has made it clear he expects Labour to deliver on its election manifesto commitment to hold a referendum on voting reform, if co-operation is to continue.

Labour refused to confirm the figures quoted in a series of papers but said around 1,000 submissions had been put forward as part of the internal consultation exercise.

The process is designed to allow party members to have their say on the policy before their annual conference in the autumn.