The private consultancy firm that lost secret information on tens of thousands of criminals could lose millions of pounds worth of government contracts.

Jacqui Smith, the Home Secretary, described the loss of the data by PA Consulting as “completely unsatisfactory” and said that the company was in breach of its contract with the Home Office.

PA Consulting, which also advised the Government on the national ID card scheme, told the Home Office on Monday that a computer memory stick holding details of all 84,000 prisoners in the country had been lost.

The storage device also contained highly sensitive information about 33,000 prolific offenders and 10,000 “priority” criminals whose whereabouts was being tracked.

The company, which made a profit of £52.5 million from its global consultancy business, is refusing to say whether the data was lost at its offices or whether an employee took the memory stick home.

Adam Adams, its spokesman, said: “We are collaborating closely with the Home Office on this matter. We have no further comment to make at this time.”

The Scotland Yard inquiry into the data loss is focused on the company’s office and a number of employees are understood to have been interviewed.

Ms Smith made no secret of her anger with the consultants in interviews. “This was data that was being held in a secure form, but was down-loaded on to a memory stick by an external contractor,” she told the BBC.

“It runs against the rules set down both for the holding of government data and set down by the external contractor and certainly set down in the contract that we had with the external contractor.”

Home Office data security was upgraded after a series of scandals over the loss of confidential data by public bodies, including the disappearance of the bank details of 25 million child-benefit claimants. Civil servants were given ten “golden rules” to follow.

The Government’s review of data security, published two months ago, said that contracts with consultants would incorporate the new data security rules. A spokesman said that the Home Office required consultants to keep confidential personal data safe, secret and secure.

“These requirements were reflected and reinforced in the contract concerned,” the spokesman added.

HM Revenue & Customs said yesterday that it had lost saliva samples from 12 suspected smugglers detained at Heathrow airport. The material, which was to be put on to the DNA database, went missing in transit.

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