About 3,000 blank passports and visas have been stolen from a van en route from Manchester to London.
However, the passport service said the documents could not be used by thieves because of their high tec security features. They are thought to be the new electronic type which contain a chip replicating the information on the document itself.
A spokeswoman from the Foreign Office admitted a breach of security had taken place. It has been suggested the passports are worth around £1,700 each on the black market.
Greater Manchester Police said the robbery took place just under half a mile away from the factory in Oldham where the passports are produced. They were to be sent to British Embassies around the world.