First Minister Alex Salmond returns to the political fray this week after the Easter break buoyed by another poll that suggests he may be gradually winning the argument for independence.

The latest tracker poll by TNS System Three suggests a narrow majority in favour of independence by 41% to 40% over those who would prefer to remain in the UK, but, as in the case of another poll last week, it is the trend that tells the real story.

Mr Salmond will believe that he is on a winning track, allowing rows to bubble up with the Treasury or Scotland Office - fights as often picked by Westminster rather than Holyrood - and then portraying Scotland as being "bullied" by London.

Whatever the reason, and despite recent spats over local income tax or council spending, it may also be that Scots in general think the SNP is making a decent fist of running a government. The point about the TNS polls is that they now show a trend.

They have asked the question a Salmond government would wish to put to a referendum in 2010, a straight yes or no to the proposition: "The Scottish Government should negotiate a settlement with the government of the UK so that Scotland becomes an independent state."

Commissioned by the the Sunday Herald, the first poll last August showed 50:35 support for the Union over independence. By November that had narrowed from 15 points to just four, 44:40.

Now the latest poll, conducted in the last days of March and the beginning of April puts independence support ahead.

Last week there was a similar trend in a second snapshot by Scottish Opinion. Last August, support for the Union led by 18 points, a 49:31 lead, but by this months that had narrowed to just two points, 43:41.

Mr Salmond claimed the actions of the Westminster "bullies" would only increase calls for independence, adding: "The more Westminster tries to lay down the law north of the Border in clearly devolved areas, the greater the support there will be for independence and equality for Scotland.

"Bullies always get their comeuppance, and the reaction to this behaviour from London will be no different. Whoever is running London Labour's campaign of aggression against the Scottish Government, one thing is clear - it isn't anyone based in Scotland, or with a scintilla of understanding of Scotland."

Mr Salmond also used a newspaper article to state the case for independence, saying: "In opposing independence, the unionist parties demonstrate a poverty of vision for Scotland, forever relegating Scotland to a parochial role as part of an unequal Union."

But Labour leader Wendy Alexander insisted a "steady majority" of Scots rejected independence. She argued that Scotland still benefited from the Union and the co-operation that it brought between the countries.

And she said "all the available evidence" indicated that even at times when oil prices were high an independent Scotland would struggle to maintain existing levels of public services.

Ms Alexander stated: "The people of Scotland know that in any partnership there will be good times and bad times and when one partner is down, the others reach out a helping hand.

"Throughout the three centuries of the United Kingdom partnership, this has been the case and the reason why it has survived and prospered."