23/07/2011 04:29 BST | Updated 21/09/2011 06:12 BST

Coulson Quit Downing Street Midway Through Highest Level Security Checks

PRESS ASSOCIATION -- Andy Coulson was part-way through the Government's highest level of security checks when he quit as Downing Street communications chief, it has emerged.

Cabinet Secretary Sir Gus O'Donnell made the disclosure amid questions over why Mr Coulson only had mid-level clearance.

Tony Blair's spin doctor Alastair Campbell and Michael Ellam, who worked for Gordon Brown, both went through Developed Vetting (DV) in order to get regular access to top secret papers. And David Cameron's current comms chief Craig Oliver is said to be going through the process.

Responding to a letter from Labour frontbencher Ivan Lewis, Sir Gus confirmed that Mr Coulson was cleared to "SC" level.

"DV is only required for individuals who require frequent access to the highest classification material," he wrote. "DV is a long and very resource intensive process and should therefore only be used where there is a clear business requirement for doing so.

"I am happy to confirm that I fully support the decision not to require DV at the outset.

"However, clearances are kept under review and can be upgraded at any time.

"Following a well publicised counter terrorism incident at East Midlands airport it was decided that Mr Coulson should undergo DV, given the importance of communications in handling a terrorist incident.

"This process was started in November and can take up to six months to complete. Obviously it had not been completed by the time of Mr Coulson's departure at the end of January.

"However, I can assure you that Mr Coulson was very happy to participate fully in securing DV. The decision on the timing of this process was taken purely on the basis of business requirements and his resignation had nothing to do with this process."