UK Labour leader Ed Miliband has urged Alex Salmond to "come clean" on his dealings with media tycoon Rupert Murdoch over claims emerging from the Leveson inquiry into press standards.
Speaking on a visit to Glasgow, where he joined Labour campaigners for next weekend's local government elections, Mr Miliband accused the First Minister of being a "secret undercover lobbyist" for the News Corp owner.
The remarks add to the pressure on Mr Salmond to answer questions over whether he had been prepared to intervene and lobby UK Culture Secretary Jeremy Hunt on the proposed takeover of BSkyB.
During James Murdoch's evidence at the Leveson Inquiry, an email by News Corp's director of public affairs Frederic Michel surfaced which said: "I met with Alex Salmond's adviser today. He will call Hunt whenever we need him to."
However, all parties acknowledge that Mr Salmond never in fact called Mr Hunt to discuss the issue.
It also emerged that another meeting between Mr Salmond and Mr Murdoch in 2008 went undeclared.
There was better news for the Nationalists as it emerged that the millionaire brother of former Labour MP Mohammed Sarwar and the uncle of the party's deputy leader, Anas Sarwar, had switched his allegiance to the SNP.
Mr Salmond yesterday denied he had lobbied on behalf of the Murdoch empire and, in an interview with STV News's Westminster correspondent Harry Smith, denied offering to use any influence he had at Westminster.
Mr Miliband said: "Now we discover that the First Minister was a secret undercover lobbyist for Rupert Murdoch.
"He didn't tell the Scottish people, he didn't come clean; he isn't coming clean now. What I say to Alex Salmond is he must come clean."
In respect of the 2008 meeting, deputy first minster Nicola Sturgeon told STV News: "There was an error made and the government has candidly admitted that error.
"I look at the front page of a major newspaper today and I see a significant defection from Labour to the SNP in the city of Glasgow so I'm actually feeling quite cheery today."