Scotland's first minister Henry McLeish is to face a police investigation into his affairs after it emerged he may have submitted fraudulent expense claims whilst a Westminster MP.

Police are to probe allegations that he received office allowances for an office which he was partially sub-letting.

McLeish has already been forced to pay back £9000 in expenses to which he was not entitled.

A police spokesman said: "We can confirm that an approach has been made to us regarding this matter and this will receive an appropriate response from Fife Constabulary, as would any approach of this nature."

McLeish is insisting that the expenses claim was "an error" telling the Scottish parliament last week that the matter was closed.

Opposition politicians say that McLeish must still answer questions on the affair - raising fresh concerns over the weekend that he may have broken House of Commons rules by allowing his publicly-funded office to be used for party political purposes.

The SNP's shadow minister for parliament, Fiona Hyslop, said: "It is astonishing that Scotland's first minister has flagrantly broken the rules in this way. It is an incredible and blatant misuse of public money. Every member at both Westminster and Holyrood knows that it is strictly forbidden to use publicly funded offices, staff or money for party political gain."

Hyslop called on McLeish to make a full statement on the issue. "The role of Scotland's first minister should be to lead by example by inspiring and giving confidence, but sadly, Henry McLeish has signally failed to do this, and is fast becoming an embarrassment to Scotland," she said.