A new chapter in Scotland's long legal history opens next month when the City-based international law firm Ashurst moves into its new office in Waterloo Street in the heart of Glasgow's commercial district.

The announcement in June may not have resonated much with the public, but the legal world has certainly been stirred. Whether fellow lawyers approve of Ashurst's arrival or not, there is widespread agreement about its significance to them.

The firm, whose new Scottish office is headed by the high-flying former Dundas & Wilson corporate partner Mike Polson, has 28 offices in 16 countries from Abu Dhabi to Washington, and employs 400 partners and 1800 lawyers worldwide.

It is emphatically not setting up stall to compete with Scotland's blue-chip firms, as other City firms have done by merging with Scottish players (see table), or indeed to provide services to anyone but its own colleagues in the City and elsewhere.

Having received £1.2 million of regional selective assistance (RSA) from Scottish Development International (SDI) to bring jobs to Scotland, it is also a condition of SDI's grant that these are not jobs displaced from elsewhere in Scotland.

Ashurst may, however, compete for talented graduates from the legal departments of Scotland's universities and colleges, and it has already been putting out feelers on campus.

The Glasgow office will offer legal and business support services to back its City and global operations.

It claims to be "the first international launch of an office of this nature in Scotland", and prides itself on being the "first mover" in bringing to Scotland a sophisticated version of what some call "legal process outsourcing" (a mildly pejorative term, Polson believes, and one that Ashurst does not apply to its Glasgow operation).

Whatever the arrangement is called, it will see client-facing roles in London, while the parts that are "less valuable to the client" - IT, finance and HR as well as technically complex but procedural legal work such as due diligence and disclosure - will be performed in lower-cost Glasgow, thus driving down costs for the clients who, in the corporate world at least, are increasingly "very aggressive on how cheaply it needs to be done".

The staff in Glasgow will be classified as "legal analysts" and pursue what Ashurst and others commend as a different kind of legal career from the traditional route for the 3000 or so graduates of Scotland's universities and colleges of aiming for a partnership in the venerable Scottish firms nearby.

Although not especially flattering to Scotland's legal ego, the main attraction of Glasgow is that even highly skilled people are cheaper, and that public money is available to help companies to employ them.

SDI boasts of "high-quality staff at lower cost, which means lower staff turnover and lower operating costs". It even provides a breakdown, extracted from the Hudson legal salary guide, which shows that while a London-based lawyer with a year's post-qualification experience would need to be paid between £65,000-£71,500, their equivalent in Scotland would require between £31,000 to £35,000. With five years of experience the differential becomes £102,000-£106,500 in London, as opposed to £44,000-£55,000 in Scotland.

The solicitors' trade body, the Law Society of Scotland, of which Mike Polson is a member, has been supportive of Ashurst's arrival and has worked behind the scenes to quell the concerns of members and non-members who find the new arrival of an unfamiliar entity disturbing, or even threatening.

Lorna Jack, the society's chief executive, has urged members to recognise that Ashurst's move reflects changes in the market.

Others are more concerned. Harper Macleod's chief executive, Martin Darroch, says: ''We could be heading into a perfect storm. I'm frustrated that there seems to be a lack of vision and leadership about the potential long-term effects on the Scottish legal industry."

Ashurst does not expect to be the only mover to have such operations in Scotland. Other large international UK firms such as Allen & Overy and Herbert Smith already have equivalent outstations in Belfast, and Addleshaw has consolidated part of its operations in Leeds and Manchester.

James Collis, Ashhurst's managing partner, calls the move "a hugely significant step for our business and symptomatic of the changing nature of the legal industry", where fully integrated law firms compartmentalise their work and transmit it around their own internal networks.

This striving for great efficiency has been picked up as a model by smaller firms, including forward-looking Scottish firms such as Burness Paull, whose chairman Philip Rodney sees Ashurst's arrival as a positive endorsement of Scotland's strengths .

Collis and Polson have ambitious plans to build the number of lawyers from the initial six to 30, and to double the businesses size every year. "Legal services are changing and Scotland is well placed to take advantage of this - with a talent pool in finance and HR - as well as the more exciting opportunities on the legal side," Collis says. "It's an amazing convergence of attractive elements."

Harper Macleod's Darroch remain unhappy with the thought of one of the country's biggest legal firms being paid to set up in Glasgow.

"If we were simply talking about a single law firm creating jobs in Scotland, then clearly everyone would be 100% behind it," Darroch told the Sunday Herald. "We've created almost 100 jobs over the past few years without any subsidies."

"Currently, Ashurst is not a direct competitor for legal services in Scotland and in any case there is nothing wrong with competitors entering our market. However, you can't consider this situation in isolation. There are wider principles at stake and I'm concerned about the potential long-term implications.

"This move comes at a time when the Scottish legal industry has been forced to move at a slower pace than that of England and Wales due to our regulatory framework regarding alternative business structures. We are a separate jurisdiction and those who trade in it, and are also regulated by it, are being hamstrung."

Darroch's dissatisfaction illustrates the toxic effects that the well-meant injection of large amounts of public subsidy can have in a commercial market-place.

He raises valid points that are often made when extremely well-heeled City players seek financial inducements from the taxpayer to make moves that will ­advantage their own profitability.

How big a deal this objection will appear in future depends on how well Ashurst's culture complements Scotland's already diverse legal mix, and whether the stimulus it provides gives legal Scotland - still paying the price for its boom-time over-extension - a new source of vitality.