An 2008 audit of laptops at the Government Communications Headquarters (GCHQ) showed 35 were unaccounted for, including three certified to hold Top Secret information; the intelligence and security committee said in an annual report on intelligence services. The rest of the laptops were unclassified.

GCHQ, a big eavesdropping operation similar to the National Security Agency in the United States, reports to the foreign minister, intercepts communications and translates them.

The committee said it appeared logging the allocation and subsequent location of laptops at GCHQ had been "haphazard".

"The Committee considers that this formerly cavalier attitude towards valuable and sensitive assets was unacceptable. GCHQ must ensure that it controls, tracks and monitors its equipment effectively. Now that proper processes have been introduced, we trust that this problem will not arise again."

In response, a government statement said it accepted the committee's criticism and conceded that GCHQ had been unable to account fully for all of its laptops at that time.

"However, GCHQ has no evidence of any loss of laptops or classified information," it said. "The most likely explanation in most cases is that the laptops were destroyed but without the destruction being fully recorded. GCHQ has now tightened up its controls."

The government has been repeatedly embarrassed by lapses over missing laptops and storage devices involving losses of information, such as when tax authorities lost data on 25 million people exposing them to the risk of identity theft and fraud.

GCHQ's predecessor, the Government Code and Cipher School, was responsible for Britain's greatest intelligence triumph, deciphering the codes of the Nazis' Enigma machine during World War Two.