Plaid Cymru leader Ieuan Wyn Jones is also deputy first minister in the coalition with Labour in the Welsh Assembly Government
Plaid Cymru enters the general election as a party of government for the first time in its 85-year history.
Since the 2007 Welsh assembly election the party has governed in coalition with Labour in Cardiff Bay despite the two parties' long and bitter rivalry.
Plaid holds three cabinet seats with its ministers responsible for economic development, rural affairs and culture, while party leader Ieuan Wyn Jones is the deputy first minister.
The party claims that this election marks its "coming of age" as a political force, while some of its opponents believe that the association with Labour will harm the party in its rural Welsh-speaking heartlands.
Founded: August, 1925
First MP: Gwynfor Evans, Carmarthen, 1966
Leader: Ieuan Wyn Jones
Elected members: 3 MPs, 14 AMs, 1 MEP
Ministers: 3 Welsh Assembly Government cabinet members, 1 deputy minister
In 2005 Plaid won three Westminster seats and hopes to at least double that number at this election. It is targeting two seats that it previously held, Ynys Mon and Ceredigion, and two that it holds in the assembly, Aberconwy and Llanelli.
The party dismisses claims by political scientists that boundary changes could imperil its hold on the redrawn Arfon constituency, pointing to its easy win in the seat in the 2007 assembly election.
Plaid is campaigning on the basis of the influence it might wield in the event of a hung parliament.
In particular Plaid says it will demand changes in the formula that governs public spending in different parts of the UK. The party argues that the so-called Barnett formula short-changes Wales and that the country should receive an additional £300m a year from the Treasury.
Plaid is also likely to stress its continued opposition to the wars in Iraq and Afghanistan and its opposition to major cuts in public spending.
The party is also calling for generous pension increases paid for by the scrapping of the Trident missile system and the ID card scheme.
For the first time, Plaid will not be making the constitutional status of Wales a centrepiece of its campaign.
An agreement between the four main parties in Wales to hold a referendum on further devolution of powers to the assembly has largely defused the topic as an issue in this election, although it is certain to re-emerge in future years.