Hijackers targeted the van shortly before 7am on Monday while it was heading to London carrying what is thought to be around 3,000 passports and vignettes – the blank stickers for visa stamps.

Police said the van was raided as it stopped at a newsagents in Chadderton. The driver of the van had gone into a shop when the second deliveryman was attacked and driven away in the van.

The robber then stopped the van a short distance away and fled with the boxes of passports.

However, the Foreign Office said the stolen passports were rendered unusable by new security features. It is understood the electronic passports contain a chip that replicates the data printed on the document.

A spokeswoman for the Identity and Passport Service (IPS) said: "We can't discuss these high-tech features because doing so would leave them more open to security breaches."

However, she did say that the cards contained biometric and facial recognition technology.

The new passports had been produced at Oldham-based printing firm 3M Security Printing and were destined for British embassies around the world.

A spokeswoman for Greater Manchester Police, which is investigating the incident, said "preventative action" had been taken to guard against forgeries.