MURRAY RITCHIE, SCOTTISH POLITICAL EDITOR

LABOUR'S so-called Natbusting campaign continued last night when Helen Liddell, Economic Secretary to the Treasury, rounded on the SNP for threatening constitutional chaos through the new Scottish Parliament, writes Murray Ritchie, Scottish Political Editor.

Mrs Liddell was speaking in Edinburgh the day after John Reid, the Armed Forces Minister, delivered another assault on the Nationalists who, he said, would wreck the Parliament. Mr Reid and Mrs Liddell are among a number of senior Government Ministers being drafted to help Scottish Labour in its bid to catch the SNP in the polls. Labour has promised seven days of Natbusting activity.

Attacking the SNP's talk of an independence referendum, Mrs Liddell said: ''Those who, for whatever purpose, try to suggest that the Scottish people, within the course of a single year, wish to disrupt that hard-won constitutional advance, do Scotland no service.

''As we look outward as a nation to the economic benefits our industries can bring - not just financial well-being but the good of mankind as well - it is ironic that there are those who put partisan opportunism before the economic good. The Scottish people rejected the chaos of Nationalism last May and that clear and unequivocal voice must go out to the inter-national business community.

''We have a constitutional advance that represents the settled will of the Scottish people, a Government determined to lead our economy to a prosperous future, and a business environment that applauds creativity and innovation. There can be no doubt that Scotland is a country equipping itself for a more prosperous future.''

Mrs Liddell was joined in her attack on the SNP by Scottish Industry Minister Brian Wilson who claimed the Nationalists were working on two election manifestos, one for the Scottish Parliament and one for an independent Scotland.

An SNP spokesman sought to mock Mrs Liddell's comments. ''From her comments, poor Helen Liddell must have slept through the Referendum campaign and only recently wakened up,'' he said.

''No-one following the campaign could have been in any doubt about the SNP viewing devolution not as an end but part of the process of independence. The pace of that process will be determined by the Scottish people.''

He also denied the existence of two manifestos. ''There is only one and it makes a comparison between what powers will be available to Scotland under devolution and how much greater they would be in spending and other areas in an independent Scotland.''