Senior sources within the Crown Office have claimed that Lothian and Borders Police placed them under "incredible pressure" to proceed to bring prosecutions against Tommy Sheridan and Gail Sheridan, following their arrest in November 2007 on perjury charges.

Rumours had been circulating for some time in the legal profession that the case against the Sheridans was about to be dropped. However in January the Crown confirmed that both would face charges in relation to evidence given during Tommy Sheridan's defamation action against the News of the World.

Factors such as the perceived benefit to the public interest, the reliability or otherwise of key witnesses and the potential embarrassment in the event of a "not guilty" outcome had led to speculation that matters would rest without further prosecution.

Senior sources in the Crown Office have now said that they were put under "incredible pressure" in recent weeks by Lothian and Borders Police to proceed with prosecutions against both individuals.

Lothian and Borders police told the Firm that following the report submitted to the Procurator Fiscal in March 2008, they had no further involvement in the Sheridan case.

A police spokeswoman said: "The case was reported to the Procurator Fiscal in March 2008, since then the matter has been in the hands of the Crown, as is routine."

In February 2008 the Solidarity party claimed that the police investigation into the case had cost more than £1 million. That figure is now understood to have risen to £1.8 million. Figures obtained from Lothian and Borders' Police under the Freedom of Information Act also revealed 40,000 hours of police officers' time had been taken up by the inquiry by that time.