In what appeared a united effort, Labour and the Liberal Democrats alleged that the Welsh nationalists were attempting to hide their policy which would lead to the break-up of the United Kingdom.
Dafydd Wigley, president of Plaid, was accused by Labour of trying to "dupe" the votersand the Liberal Democrats branded him "wriggley Wigley".
Mr Wigley said the two rival parties were indulging in "McCarthyism" and said Labour was becoming desperate as the chances of the Welsh Secretary, Alun Michael, securing a seat ebbed away.
Peter Hain, Labour's campaign manager, said his party had evidence which "blows away" the Welsh nationalists' claim that they were not a separatist organisation. The Welsh party had been engaged in a "systematic operation" to remove from the public eye publications which demonstrated its commitment to separatism.
Michael German, leader of the Welsh Liberal Democrats, said: "No matter how he wriggles, Dafydd Wigley cannot escape the fact that Plaid Cymru was born out of a desire to break away from England."
Ieuan Wyn Jones, Plaid's election campaign director, said that Labour's attack showed that Millbank's "darkest tendencies" were at work.
Rod Richards, leader of the Welsh Conservatives, meanwhile alleged that Gwynedd council was guilty of discrimination by refusing to employ non- Welsh speakers or those who had no intention of learning the language. He claimed the policy was costing the local authority pounds 400,000 a year.Reuse content