ALEX Salmond has endured his most bruising week since coming to power in 2007.

As the Nationalists were rocked by resignations over their Nato policy shift, the First Minister faced the nuclear bomb of political accusation – that he had "lied" during a television interview in March.

His Sunday Politics exchange with Andrew Neil, on the issue of an independent Scotland's membership of the EU, resurfaced on Tuesday and has been replayed ad infinitum since then.

For those of you who don't know it by heart yet (what have you been doing all week?) Mr Neil asked: "Have you sought advice from your own Scottish law officers on this matter?" and Mr Salmond replied: "We have, yes, in terms of the debate." He went on to stress he could not "reveal the legal advice of law officers" but, citing Government documents which claim an independent Scotland would automatically be a member of the EU, added: "Everything we publish is consistent with the legal advice we receive."

Of course we know now ministers had not consulted their law officers, the Lord Advocate and Solicitor General, on Scotland's membership of the EU at that stage.

Nicola Sturgeon confirmed as much in a statement to Parliament when she informed MSPs that advice was only now being sought in the wake of the Edinburgh Agreement on the referendum format. But, as she also subsequently acknowledged, some people had somehow gained the impression that advice had been taken, and that was "unfortunate".

It was not, by the way, the Government's fault. The First Minister's use of the words "we have, yes" in no way contributed the widespread misunderstanding, his spin doctors somewhat lamely insist. Silly us, then.

Perhaps the most generous interpretation that can be placed on this whole mess is that the Government has been careless in allowing the idea to gain ground that their claims on Europe carried greater legal clout because they had the positive endorsement of the Lord Advocate.

All that has been established is that it is not illegal for the Government to make political claims in its key documents on independence such as Your Scotland, Your Referendum, published in January.

Two things follow from this. First, and most obviously, the row over the EU will rumble on. The mechanism for an independent Scotland's entry into the EU and the terms of membership remain unclear. There are claims and counter-claims on both sides. Who knows who's right? Secondly, and potentially more damagingly, the question of trust in the First Minister and his administration has come to the fore.

Johann Lamont did not repeat the "l" word at First Minister's Questions but her description of Mr Salmond as "straight as a corkscrew" left no-one in any doubt where Labour's attacks are heading.

Mr Salmond is keenly aware of the importance of trust and the danger of losing it. It's how he won his first Scottish election, after all. In 2007, with the Iraq war dodgy dossier still fresh in people's minds, he beat Labour by simply brushing them aside. "That's Labour, they would say that, who believes them?" was, in effect, all he needed to say.

This explains why he was so eager to have himself investigated for an alleged breach of the ministerial code of conduct, which prohibits him from revealing the existence or otherwise of legal advice without the prior consent of the Lord Advocate. See? You've stopped reading. Not as interesting as a First Minister "lying" is it?

Mr Salmond is confident (and I'm sure he's right to be) that he will satisfy the civil servant and lawyers conducting the inquiry that no such transgression took place. Even if he has to scoff a morsel of humble pie over a slightly clumsy answer in the Sunday Politics interview he expects to be cleared and plans to make a proper meal of his accusers.

Will that draw a line under the matter? The SNP fervently hope so. With the biggest fight of his life now underway the First Minister cannot afford to be branded untrustworthy.