VINCE Cable has called for "proper political oversight" of the intelligence services in the wake of disclosures about the collection of communications data by the Government's secret eavesdropping station GCHQ.

The Business Secretary said The Guardian newspaper had performed "a very considerable public service" in publishing secret material leaked by whistle-blower Edward Snowden, which revealed the extent of mass surveillance programmes operated by the US National Security Agency and Cheltenham-based GCHQ. He confirmed reports that Deputy Prime Minister Nick Clegg was seeking a rethink of how politicians oversee the intelligence service.

Mr Cable's comments came as a senior Whitehall security expert said the Snowden leaks amounted to the "most catastrophic loss to British intelligence ever".

Sir David Omand, the former head of GCHQ, said the leak of files by the former US intelligence operative eclipsed the Cambridge spy ring, which saw five students recruited as Soviet spies.

Earlier this week, MI5 head Andrew Parker said the Snowden leaks were a "gift" to terrorists. His comments sparked criticism in some quarters of The Guardian's decision to give Snowden publicity.

But Mr Cable defended the newspaper, saying: "I think The Guardian has done a very considerable public service. The conclusion that Nick Clegg came to and set out this morning is that we do need to have proper political oversight of the intelligence service and arguably we haven't done until now.

"What they did as journalists was entirely correct and right. Mr Snowden is a different kettle of fish."

Aides to the Deputy Prime Minister told The Guardian that Mr Clegg was considering how to update the legal oversight of Britain's security services.