A Libdem MSP whose election expenses are being investigated by the police claimed the rent on his campaign office cost less than his bill for tea and biscuits.

Alex Cole-Hamilton, who won Edinburgh Western from the SNP in May, spent just £83.45 renting a shared office for 122 days, or 68p per day, according to his election return.

Over the same period, his “coffee/tea/biscuit supplies for volunteers” amounted to £180.

The SNP, which rented the office next door in Corstorphine for £760, said Mr Cole-Hamilton's rent deal was so low he should have declared it as a donation in kind.

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Police are currently investigating alleged “financial irregularities” in Mr Cole-Hamilton’s election expenses after a member of the public claimed he under-declared his costs.

With Edinburgh Western a key LibDem target, Mr Cole-Hamilton, 38, spent £32,549 on his campaign, 75 per cent more than his SNP rival, Toni Giugliano, who spent £18,593.

Mr Cole-Hamilton was a “dual candidate”, standing in both a seat and topping the LibDem regional list in Lothians, and was required to make an “honest assessment” of whether his spending promoted the constituency or regional campaign.

He only stayed under the legal spending cap in Edinburgh Western by attributing thousands of pounds of leaflet and office costs to the regional fight instead of to the constituency one.

He went on to win by 2,960 votes and is now the LibDem health spokesman at Holyrood.

LibDem sources said Mr Cole-Hamilton enjoyed the same peppercorn rent on his campaign office as its previous occupant, Michael Crockart, the former LibDem MP for Edinburgh West, as the letting agents wanted to keep the property occupied.

After Mr Crockart lost his seat to the SNP in 2015, his office lay empty for nine months and Mr Cole-Hamilton’s team snapped it up for the same monthly service charge of £34.86.

This minimal cost was then split 60:30:10 between Mr Cole-Hamilton’s constituency campaign, the LibDem regional campaign in the Lothians and the local LibDem branch.

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Mr Cole-Hamilton then spent an additional £3192 on rates, insurance and utilities in relation to his campaign office, compared to £3649 spent by the SNP.

A spokesman for the Edinburgh Western SNP said: “If a donation in kind was made and not declared this is extremely serious."

A Scottish LibDem spokesman said: “All costs are fully in line with spending rules and were recorded and declared forensically in election returns."