Iwan said Plaid was the only party to trust

Speaking to delegates at the party conference in Caernarfon, he said he was offering the people of Wales a "people's contract".

He said the contract would spell out the party's commitment in terms of Wales and the world as a whole.

In the next election, he said, Plaid was "the only party you can truly trust".

Later, in a strongly-worded attack, Plaid parliamentary leader Elfyn Llwyd said New Labour had spread "fear, war and death to the world."

The Meirionnydd Nant Conwy MP told delegates in Caernarfon that Plaid was a socialist party "and proud of it".

The party hopes the conference will be a launchpad for a May general election.

Plaid, which has been strongly opposed to the Iraq war, has already tried to have Mr Blair impeached over the conflict.

Mr Llwyd used the slogan "Blair lied, vote Plaid" in his speech on Saturday.

'Socialist antidote'

Plaid has done better at Welsh assembly elections than at Westminster since devolution in 1999.

The party will want to build on its performance at the last general election in 2001. It was placed second in terms of its MPs, with four out of the 40 in Wales, although Labour was way out in front with 34.

But in terms of total votes cast, Plaid was third behind Labour and the Conservatives - although the Tories have had no Welsh MPs since 1997.