British Airways (BA) is considering suing airport operator, British Airports Authority (BAA), for compensation after security measures forced it to cancel hundreds of flights from Heathrow Airport, according to BBC report.

BA boss Willie Walsh attacked BAA's management, saying it had "no adequate plan to keep the airport functioning properly" in the emergency, BBC reported on Tuesday.

But BAA said security searches meant that delays were still likely, and anyone travelling over the next few days should allow extra time for their journey.

BAA has come under fire from several airlines who have been highly critical of the way BAA has managed airports since last Thursday when the UK security threat level was raised to "critical " in the wake of alert over a possible terror plot.

BA said that it had cancelled 700 Heathrow flights since last Thursday, and some 10,000 bags had gone missing and 5,000 bags still need to be returned.

Flights cancellations and delays are set to move into a sixth day at Heathrow airport. On Tuesday, a total of 45 flights have been cancelled at Heathrow, including four BA long-haul services, 21 short-haul and 16 domestic flights.

Meanwhile, all UK airports have relaxed the restrictions, on Tuesday, on hand luggage introduced last Thursday when passengers had been banned from taking anything into aircraft cabins except travel documents, baby food and certain medicines, all of which had to be carried in clear plastic bags.

The new guidelines are allowed passengers now to take bags, no bigger than 45cm x 35cm x 16cm, with them into aircraft cabins, including wheels, handles and side pockets.

But people are still not allowed to take in any liquids apart from baby milk and baby food, and prescription medicines.

(Xinhua News Agency August 16, 2006)