The home secretary, Jacqui Smith, was last night facing a Commons summons to explain how another batch of secret documents were left on a train.
Papers covering global terrorist funding, drug trafficking and money laundering were found last Wednesday in a carriage heading for London's Waterloo station. They were said to include details of how banking systems could be manipulated to finance illicit weapons of mass destruction in Iran.
It comes after secret service reports on Iraq and al-Qaida were found on a separate train last week and passed to the BBC. Those papers included secret Joint Intelligence Committee assessments.
"We need an explanation from the home secretary whether all these breaches of security affect our fight against terrorism," said Keith Vaz, chair of the Commons Home Affairs Committee. "No official, no matter how senior, should be allowed to take classified or confidential documents outside their offices, for whatever reason."