They normally weigh the Labour vote in Blaenau Gwent, which was represented at Westminster by Aneurin Bevin and Michael Foot for more than 50 years, but in this election the Labour leadership faces an extraordinary insurrection led by a rebel member of the Welsh Assembly who is recovering from surgery for a brain tumour.
Peter Law was expelled from the party after 40 years when he protested about the imposition of an all-women shortlist in the Valleys constituency, the safest Labour seat in Wales. After getting the go-ahead from his doctor, Mr Laws, who represents Blaenau Gwent in the Assembly, is fighting a vigorous campaign, condemning the interference from party headquarters and demanding a return to Labour's socialist roots.
Peter Hain, the Secretary of State for Wales, has dismissed him as a "fringe, non-Labour politician", while David Blunkett, the former home secretary, visited the constituency with a plea to disaffected Labour supporters not to vote for "dilettant" candidates.
Mr Law said yesterday: "New Labour have used every trick in the book against me. They took away the right of choice from Blaenau Gwent. It really stinks. We've been used for a social experiment and manipulated." Such is his impact that the former MP, Llew Smith, whose majority in 2001 was 19,313, predicts that Mr Law will win.
The contest for Blaenau Gwent is the most spirited in Wales, where only a handful of seats are likely to change hands. Just three Labour constituencies appear vulnerable. Cardiff Central could fall to the Liberal Democrats, partly because of the introduction of university fees. The constituency has a high number of student voters - a large percentage of whom say they will turn out.
Prosperous Monmouth near the English border could be taken by the Conservatives. Many voters in the Gwent market town are unhappy with the ban on foxhunting. Another seat that Labour might lose to the Tories is Clwyd West, an area made up largely of villages and not traditional Labour territory.
Of the 40 constituencies in the principality, Labour took 34 in the last general election, Plaid Cymru four and the Liberal Democrats two. Wales was a Tory-free zone. In the Welsh Assembly however the Conservatives have a substantial presence. Out of 60 seats they hold 11, with Plaid Cymru 12, Liberal Democrats six and two Independents, including Mr Law. Until this week Labour, with 30 members, enjoyed a majority of one - a Plaid member was the Assembly's presiding officer.
Anger over the Assembly's stewardship of health - one of the policy areas devolved to Wales - could affect voting intentions in the general election.
Many voters in Wales believe the English have got their act together over the NHS. One senior trade unionist put it down to the fact that "incentives for success and the penalties for failure are stronger in England". Welsh Conservatives said the British Medical Association had declared it had no confidence in Labour's handling of the National Health Service in Wales.
Paradoxically while voters harbour reservations about the Welsh Assembly, it is attracting far more support than it used to. The principality's parliament was invested in 1999 under Labour's policy of devolution. It was established after a wafer-thin majority in a referendum. The Assembly is responsible for education, health, local transport and other public services but, unlike the Scottish Parliament, has no power on tax rates.
An ICM poll for BBC Wales asked voters what level of government should have the most influence over the principality. Fifty per cent opted for the Assembly, but only 23 per cent chose the UK Government. Just 25 per cent thought the Assembly should be abolished, 19 per cent said it should remain as it was, while 52 per cent believed it should be given more powers.
Politicians believe that despite the problems over health, voters are starting to realise that the Assembly is responsible for some popular policies, such as free bus passes for all pensioners.
For all the concern over health and education, it could well be "the economy stupid". Here Labour's record is patchy. While unemployment is at its lowest for 30 years, the quality of the jobs on offer is not high.
The level of pay in Wales never really recovered from the collapse of heavy industry during the Thatcher years. The manufacturing sector has been in decline like elsewhere in the UK.Reuse content