Labour will accuse the nationalists of changing the text on their web site in an attempt to airbrush any suggestion that they favour the break- up of the United Kingdom. Peter Hain, a senior Labour Party figure in Wales, will allege that Plaid Cymru routinely called for independence in past years and will argue that the party is trying to reinvent its history.
Dafydd Wigley, President of Plaid, has consistently argued that independence was never one of his party's policies.
The most recent polls show significant gains by the nationalists since the general election. Whereas in 1997 Plaid gained just 10 per cent of the vote, pollsters believe they will gain nearly 20 per cent of the 40 seats in the Welsh Assembly elected on the principle of first past the post.
Even more worrying for Labour was the finding that the nationalists could gain 29 per cent of the 20 seats elected through proportional representation.
Clearly the most powerful party in the principality, Labour is worried that while the party will take a clear majority of first-past-the-post votes, there may be a "protest" vote by loyal supporters who may cast their second vote for another party from the "top-up" list of candidates.
Heading Labour's list is Alun Michael, Secretary of State for Wales, parachuted in by Tony Blair because of his New Labour credentials. Mr Michael stands accused by his critics of seeking to ensure that the Assembly simply toes the Westminster line. Rhodri Morgan, whom he defeated for the leadership of the Welsh party, and Ron Davies, who resigned from his post as Welsh Secretary after his walkabout on Clapham Common, both want the parliament to make its mark.
One of the paradoxes of the new electoral system is that a massive vote for a party's candidate in the first-past-the-post element of the poll will make the success of the party's "list" candidate less likely.
Supporters of Mr Morgan have been out in force in key constituencies in the Mid and West Wales area attempting to maximise the votes for Labour constituency candidates. The complexities of the voting system mean that some Plaid Cymru supporters in the key Carmarthen East constituency are hoping for a big Labour victory so that Mr Michael is defeated.
All candidates face widespread apathy among voters. If Labour is suffering from the relative unpopularity of its leader in Wales and Plaid Cymru is battling against its separatist image, the Conservatives are not without their problems.
The Tories are split from top to bottom in the principality. Rod Richards, the party's leader in Wales, represents the right-wing Eurosceptical tendency, while the politician he defeated for the top job, Nick Bourne, is a more orthodox Conservative who enjoys the support of the party leader, William Hague.Reuse content