The Scottish Labour leader, Johann Lamont, has seized upon the YouGov poll on trust in Alex Salmond as confirmation that the Scottish voters do not believe a word the First Minister says.

Labour politicians, including Paul Martin MSP, have recently accused the First Minister of being a "bare-faced liar" over issues such as the legal advice on EU membership after independence. They will no doubt use this opinion poll as ammunition in their target practice on the SNP leader's probity.

However, these figures mean little in isolation because questions were not asked in the sample about the trustworthiness of the SNP leader's political rivals.

Trust in all politicians is at an all time low; they are even less trusted than estate agents, according to some opinion polls. So, it is perhaps not surprising that only 35% of respondents say they trust Mr Salmond "a fair amount or a great deal". Some 30% say that they "do not trust him at all". If we include the 25% who say they "do not trust him a lot", this negativity rating rises to 55%. Equally, it could be said that 60% of respondents have some degree of trust in the First Minister.

The Nationalists will not be too worried, therefore, about the headline figure. What should perhaps concern the SNP is that many more men than women appear to trust Mr Salmond, and more middle aged people trust him than those under 30 years of age.

The Scottish Government has been making overtures to the women's vote recently with the promise of free child care in the White Paper on independence. And the Yes Scotland campaign prides itself on its ability to use social media to connect with young Scots and inspire them with the idea of self-government.

On these figures, the First Minister has some work to do if he is to ignite trust among these key groups. He also has some persuading to do with wealthier Scots who appear to find him less trustworthy than working-class Scots do.

However, as with all opinion polls, the results depend very much on the questions that are asked. On other measures, the First Minister is still remarkably popular for a leader who has been in office for seven years.

In the most recent Panelbase poll in September last year, as reported by The Herald, Alex Salmond had an approval rating of plus 11, meaning that more people approved of the First Minister's performance than disapproved.

By comparison, the Prime Minister, David Cameron, had an approval rating of minus 45, meaning that many more disapproved than approved. The Labour leader, Ed Miliband came in at minus 46 and the Liberal Democrat leader, Nick Clegg, at minus 53.

Labour claim that Johann Lamont also has a positive approval rating in Scotland. However, this is difficult to measure accurately because few Scots are familiar enough with the Scottish Labour leader to make a considered judgment.

As the Herald reported last December, 45% of women in Scotland did not appear to know who she was.