A second batch of secret government files has been found on a train, a British newspaper reported.
The Independent on Sunday, in a preview made available late Saturday, said the papers dealt with Britain's approach to tackling the financing of global terrorism, the drugs trade and money-laundering.
The newspaper said the documents were found on a train bound for London on Wednesday, the same day another batch of secret documents on al-Qaeda and Iraq were handed to the BBC after being left on a train.
The BBC said those documents, stamped "UK Top Secret", carried assessments of al-Qaeda's vulnerabilities and the capabilities of Iraq's security forces.
The Independent on Sunday said it had returned the documents and would not be publishing any of the details they carried.
It was not immediately clear where the documents came from or which government body was responsible for their security. Britain's Cabinet Office, which coordinates policy across various government departments, did not immediately return a call seeking comment. Neither did the country's Treasury.
London's Metropolitan Police said it was not involved in the incident.
The British government has suffered a series of highly embarrassing security breaches. An unencrypted computer carrying information on 600,000 prospective military recruits was stolen from the car of a Royal Navy recruitment officer in central England in January.
In December, the government's top transport official said a disc containing personal information of 3 million driving-test candidates was lost. The same month, the Department of Health said information on about 168,000 patients had also gone missing.
But those incidents were dwarfed by the admission, in November, that tax officials lost computer discs containing information - including bank records - for 25 million people, nearly half the country's inhabitants, according to The West.