The introduction of fingerprinting was brought to a halt just hours before the new state-of-the-art terminal opened, following data protection concerns raised by the Information Commissioner's Office.

The ICO has begun an investigation into data protection and the new fingerprinting system, focusing on passengers transferring on to domestic flights at T5.

In a statement, an ICO spokesperson explained: "We have concerns about the routine collection of fingerprint information from passengers and we will require reassurance from [Terminal 5 operator] BAA that the data protection implications of the proposals have been fully addressed.

"We will be weighing up the security benefits of the scheme against the impact on privacy and asking what other, less intrusive alternatives have been considered."

A spokesperson at BAA said passenger photos would be taken "temporarily" instead, adding: "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."

Not long after BAA announced it would not fingerprint passengers, a sophisticated IT system aimed at cutting baggage handling times broke down. According to reports, arriving passengers were left stranded for up to two and a half hours, while "technical" problems were resolved to enable BAA to return their luggage.

The baggage problems will come as an embarrassment to the airport operator which has long touted the system's benefits. It was designed to process up to 12,000 bags per hour, and more than 400,000 hours of software engineering went into developing it.

Fingerprinting is one of many hi-tech systems being used at the new terminal, which is entirely dedicated to BA flights. BA said the use of technology would help reduce the passenger congestion problems suffered by the airport's other main terminals which are running at more than capacity, as well as assisting baggage handling and check-in.

The terminal has cost BA and the British Airports Authority £4.3 billion to build and outfit. BA says it spent £75 million on technology, while BAA invested a further £175 million.