The broadcast, due to be screened north of the border tonight, begins and ends with a voice-over from the former 007 star ? the SNP?s most celebrated supporter and financial backer ? and includes interviews with ?ordinary Scots?, two of whom turned out to be party workers.

When a press preview was shown at SNP headquarters in Edinburgh yesterday, the two party workers, one of whom works for the SNP in the Scottish Parliament, were almost as instantly recognisable to journalists as Sir Sean himself.

The Nationalists rebuffed hostile questions with Nicola Sturgeon, the party?s deputy leader, saying: ?What we have done is take people from all over Scotland and different walks of life, to tell people why Scotland matters to them.

?Just because you work for the SNP parliamentary group doesn?t mean you are not an ordinary Scot and somebody who feels very strongly about Scotland.?

Sir Sean?s part in the broadcast begins with him asking: ?What is it about Scotland that matters to you??

A succession of what the broadcast describes as ?ordinary Scots? are then seen itemising their main concerns or interests.

The broadcast also ends with Connery?s voice urging viewers: ?Vote SNP, Scotland?s party. Why? Because it has been acknowledged and voted to be the most trustworthy political party of them all.?

Last night other parties in Scotland were checking their election broadcasts to find out whether they would face similar questions about the use of party activists.

This is the second time that the actor has been caught up in controversy during this election campaign.

Last week it emerged that the SNP risked prosecution and massive financial penalties by using automated telephone messages, featuring Sir Sean?s voice. The SNP is alleged by opponents to have already breached strict rules on the use of this technology.