HOLYROOD'S longest serving independent MSP has hailed the pledge of a full police investigation into rendition flights as a triumph for backbenchers holding Ministers to account.

Margo MacDonald, the only MSP currently elected as an independent, sits with the so-called "Grindies" – the two Greens and the two MSPs who resigned from the SNP over the party's conference vote to remain in Nato.

Her question to Lord Advocate Frank Mulholland at Holyrood prompted his announcement this week.

He said he was ordering the police to investigate evidence, gathered by researchers at Kent and Kingston Universities, of an extensive database of flights suspected of being used by the CIA to shift prisoners around the world which have touched down on Scots soil.

Police have already looked at similar evidence in relation to Prestwick, Glasgow and Edinburgh, but their latest research builds on that and adds further detail regarding airports in Aberdeen, Inverness and Wick.

Mr Mulholland told MSPs: "It is very important that there should be no dilly-dallying in this matter.

"I am confident that the police will conduct a thorough inquiry."