BAA’s plans to fingerprint all passengers travelling through Heathrow’s new Terminal 5 have been put on hold after concerns were raised about the legality of the security measurement.

UK’s data protection watchdog, the Information Commissioner, is investigating the plan after a complaint by a privacy campaign group.

As arriving and departing passengers from both domestic and international flights are mixed on arrival to Terminal 5, the BAA decided to take fingerprints of all passengers on check-in desks and at the departure gates to ensure those checked in are boarding the plane.

But there are concerns that taking fingerprints is an invasion of privacy.

A BAA spokesman said: “We will be working closely with the Information Commissioner and the Home Office over the next few weeks to agree the best approach going forward.”