Information Commissioners in both Scotland and England have been urged to intervene in a bid to have the UK Government reveal details of unpublished polling on attitudes to independence.

SNP MSP Bruce Crawford has written to both Christopher Graham in England and his counterpart in Scotland, Ken Macdonald.

The UK Government has faced repeated calls from the SNP to make public the findings of the research, with Mr Crawford claiming £300,000 of public cash had been spent on it. In his letters, he claimed the "true cost of the polling conducted by the UK Government on the independence referendum is in fact £299,100, substantially more than previously admitted". He said that "while this level of Government expenditure on political polling should always be considered worthy of public scrutiny", this was "perhaps even more necessary" after press reports that the findings have been shared with the Better Together campaign to keep Scotland in the UK.

The former Scottish Government minister said he had contacted the Information Commissioners because the UK Government has failed to publish the details following Freedom Of Information (FOI) requests. Mr Crawford said: "The UK Government has spent £300,000 of public money on what is essentially private polling for the No campaign - it is unacceptable that taxpayers are expected to bankroll the No camp in this way."

Scottish Secretary Alistair Carmichael was called on to publish the polls when he appeared before MSPs at a Holyrood committee last month.

A UK Government spokesman said: "These costs have been openly and transparently put into the public domain via the Cabinet Office website. It's normal practice for governments to carry out this sort of polling, especially around an issue as important as the referendum.

"We are carrying out this research to understand how best to identify and communicate with our audiences."