THE Liberal Democrats came under attack today as an "extremely unreliable partner’’ in coalition talks.

Plaid Cymru leader Ieuan Wyn Jones warned both Labour and the Conservatives to look at the Lib Dems' record in Wales when deciding whether to approach them in the event of a hung Parliament.

"The last time the Liberal Democrats were asked whether they wished to form a government, they came within a whisker of doing it but walked away at the 11th hour,’’ he told a press conference in Westminster.

"That, I think, should be a lesson to anybody.’’ Mr Wyn Jones's comments came as both the Welsh and Scottish Nationalists again ruled out joining a formal coalition if no party has an overall majority on May 7.

Plaid Cymru and the SNP would vote on an "issue by issue’’ basis in the best interests of the people of Wales and Scotland.

SNP leader Alex Salmond said a hung Parliament had now become "all but a certainty’’.

"Such a parliamentary outcome would present a massive opportunity for the people of Scotland and Wales,’’ Mr Salmond said.

"We intend to take that opportunity.

"We would deploy our voting strength in the interests of the people of our nations.’’ And Mr Wyn Jones said: "If you actually look at the way coalitions are done throughout the world, it would be absolutely foolish for us to go into any discussions with any party in Westminster in terms of a coalition.

"That is what the SNP and ourselves are totally united on.’’ The party leaders pledged to act as a "Celtic bloc’’ to secure a four-point agenda of fair funding for Wales and Scotland; protecting local services most vulnerable to the "cuts agenda of the London parties’’; action to help the green economy; and support for business growth across the two countries.