A LABOUR high-flier who stood at the last Holyrood election and helped the party develop pioneering computer software will today defect to the SNP during its conference in Inverness, blaming Tony Blair's stance on Iraq as the last straw.

Gordon Guthrie, 39, stood for the party in West Aberdeenshire and Kincardine in 1999 and was on the approved candidates' list for the next election, where he was still in the running to contest Aberdeen South in May.

He has spoken of growing disillusion with Labour's handling of the Scottish economy pushing him towards the SNP on this issue, but it was Mr Blair's ''grotesque'' stance on Iraq that pushed him over the brink.

Mr Guthrie was a New Labour moderniser who was fully behind the Blair revolution, although he came a poor fourth at the last election and has not secured a selection this time.

But the fact he is taking his inside knowledge of Labour's computerised canvassing system to the SNP is certain to cause concern at his former party's headquarters in Glasgow.

Mr Guthrie served on the Scottish Office's knowledge economy working party before becoming a senior figure in Scottish Computing for Labour. It was there that he worked to develop the party's cutting-edge electoral computer software.

He also wrote for Marxism Today and the Belfast political journal Fortnight before teaming up with other political analysts such as Gerry Hassan at the Scottish Nexus Group.

Roseanna Cunningham, deputy leader of the SNP, will parade the party's capture in Inverness today. She told The Herald: ''Gordon Guthrie's decision to join the SNP is a reflection of the strength of argument that the party has deployed in campaigning for independence.

''With an election looming, Gordon has already made a choice that is facing everyone - whether to continue paying the price of staying in the UK or to seize the opportunity to release Scotland's potential and deliver independence.''

Mr Guthrie, who was born in Trinidad when his father was working there, was scathing about the government's stance on Iraq. He said: ''The current US administration is plainly unilateralist and contemptuous of international law. Europe, including Scotland, is firmly multilateralist.

''It is grotesque in these circumstances to find a Labour government scurrying around issuing ultimatums to the UN, at odds with our European partners, and in cahoots with a right-wing American administration whose values are not our values and whose goals are not our goals.''

Similarly, on trade and economic issues he said: ''It is clear that the governance of our common economy in Europe is the major domestic issue. For Labour to be facing west across the Atlantic at a time when our economic destiny is in the balance in the east across the Channel is lunacy.''

He accused Mr Blair of ''seeking the appearance of influence over the US and walking away from the exercise of true power through the EU''. In contrast, he said: ''The SNP's brave contribution to the debate on Iraq has made it abundantly clear that we in Scotland have another choice, another voice, firmly unilateral and European.''

Mr Guthrie said his decision had been arrived at over time and he singled out the work of Andrew Wilson, shadow minister for the economy. He said he wanted to see Scotland become a modern European nation, with high levels of social provision, a dynamic attitude towards entrepreneurship and growth, underpinned by constitutional reform and devolution of power.

He added: ''The recession and war with Iraq have dramatically highlighted the constitutional question and convinced me that Scotland needs 'the normal powers of a normal country', as John Swinney puts it.''