By David Cornock BBC Wales Parliamentary correspondent

Tony Blair hopes voters will be playing ball at election time

In the absence of fixed-term parliaments and a written constitution, historians have to rely on other sources for such information.

The Sun newspaper, which predicted the 2001 poll date correctly, has announced that Tony Blair will try to win an historic third term on 5 May.

Forty seats in Wales are up for grabs.

Last time, only two of these seats changed hands politically, with Plaid Cymru taking Carmarthen East and Dinefwr from Labour and Labour taking Ynys M�n from Plaid Cymru.

The election ushered in a handful of new MPs, some replacing Welsh assembly members retiring from Westminster, but otherwise did little to threaten blood pressure levels.

Let us hope the 2005 campaign offers more to stimulate the voters, although opinion polls suggest that, despite Labour's political difficulties (Iraq, David Blunkett, the NHS in Wales), Tony Blair is on course for a third term.

The Conservative leader, Michael Howard, has spoken of his frustration at failing to make an impact despite Labour's woes.

The Tories have failed to win a seat in Wales during the last two elections. A hat-trick of failure west of Offa's Dyke would leave Tony Blair in Downing Street.

The repercussions of David Blunkett's affair could hurt Labour

The Conservative AM for Monmouth, David Davies, hopes to win the highly marginal parliamentary seat for the party but, if the Tories are serious about winning power, they also need to win back seats like Clwyd West, Conwy, Brecon and Radnorshire, and the Vale of Glamorgan.

The party insists that its private polling shows it is doing better in closely-fought marginal seats, and it could benefit from a low turn-out by disgruntled Labour voters, but there is little independent evidence to bring much cheer to Mr Howard.

The Liberal Democrats hope to take Cardiff Central from Labour. The Lib Dems hold the seat in the Welsh assembly and hope to exploit student unhappiness over tuition fees to replace Jon Owen Jones with Jenny Willott.

Plaid Cymru will hope to retake Ynys M�n, the seat of their assembly leader Ieuan Wyn Jones.

The party took a battering during the 2003 assembly and 2004 European elections, despite declaring the latter to be a referendum on the unpopular war in Iraq.

No opposition politician has succeeded in highlighting Iraq as consistently as Adam Price, who has made more impact during his three years as an MP than some make in a lifetime.

But it remains to be seen whether his successful pursuit of headlines in the English media will deliver votes locally.

Will Adam Price's move to impeach Tony Blair help him keep his seat?

The editor of the Spectator, Tory MP Boris Johnson, says Mr Price's campaign to impeach the Prime Minister over Iraq stands "not a snowball's chance in Hades" of success, and domestic issues may yet prove more decisive in the election.

Falls in unemployment and house price rises may help create an economic "feel good" factor that helps Labour keep power despite stealth tax rises.

Spending on public services has increased dramatically, although whether it has delivered similar improvements in their quality is questionable, particularly when it comes to the Welsh Assembly Government's record on the NHS.

There will be other issues on the election agenda.

Three of the four main parties in Wales will enter the campaign committed to giving the assembly more powers.

Labour says that if re-elected, it will bring forward proposals that could see the assembly gain law-making powers.

Most Welsh Labour backbenchers at Westminster are pretty unhappy about this prospect.