This operation demonstrates that when reasonable information is received we will investigate vigorously

Scottish Parliament spokeswoman

Those being targetted work for subcontractors of the parliament's construction managers, Bovis, it is understood.

A spokesman for the Scottish Parliament said: "The parliament was notified in advance by Lothian and Borders Police that there would be a benefits agency check of staff on site.

"Such checks are commonplace in the construction industry.

"In the lead-up to today's check, Bovis Lend Lease, the parliament's construction managers, have co-operated fully with the investigating authorities and will assist in any way should there be any follow-up enquiries."

Costs controversy

A parliament spokeswoman added: "It is too early to say what the outcome of this exercise will be and we are not sure yet exactly how many people may be involved in benefit fraud.

"We take benefit fraud seriously and this operation demonstrates that when reasonable information is received we will investigate vigorously."

The new parliament building has been at the centre of controversy because of spiralling costs.

David McLetchie: "Black hole"

At the end of last year, the figure had risen to nearly �260m.

It is hoped to have the building open in time for the next parliamentary elections in May 2003.

Scottish Tory Leader David McLetchie said the "Holyrood black hole was now financing the black economy".

"Nothing has done more to tarnish the reputation of the Scottish Parliament than the handling of the Holyrood building project," he said.

"The whole sorry saga has been characterised by incompetence, mismanagement and misinformation from day one."

He called for the Scottish Executive to take some responsibility for the project by putting a minister on the Holyrood Progress Group.