UK airport authority BAA has announced that it plans to ease security restrictions in place on domestic and international flights at its airport, but that the changes will not come into effect until tomorrow.
The company has also ordered airlines to cancel a third of flights due to depart from London's Heathrow airport today, despite the government's decision to ease hand luggage restrictions.
The Department of Transport announced this morning that it had lifted the ban on taking hand luggage onto flights after the Home Office announced that the terror threat level facing the UK had been downgraded from "critical" to "severe".
Air passengers will now be permitted to carry one item of cabin baggage onto flights, although with liquids of any kind, barring prescription medicines and baby food, will still be prohibited.
But in a statement, the UK airports operator BAA said that it would not be able to implement the changes at London's Heathrow and Gatwick airports until tomorrow morning.
In a statement on its website, BAA said it was "looking to introduce the changes as quickly as possible" but that passengers would still not be permitted to carry hand luggage onto planes for the present time.
"To ensure the safety and security of our passengers, BAA is now setting up the appropriate structures, procedures and operational logistics required to implement these new regulations".
"From 04:30 BST on Tuesday August 15th passengers will be able to take one small cabin bag,", - measuring no more than 16cm by 35cm by 45cm - the company stressed, adding that it would publish further details of the revised restrictions on hand luggage soon.
A spokesman for BAA today said that it intended to allow passengers to take previously restricted items such as car keys, mobile phones and laptops onto flights, but controls on cosmetics, toiletries and liquids would remain in place.
However, the representative added that the travelling ban imposed on prescription medicine and baby milk had now been lifted. Air travellers are also able to take items purchased in the departure lounge onto planes, but he emphasised that this was not the case for US-bound flights.
"BAA would like to thank passengers and staff for their patience and the airlines for their cooperation. We would also like to thank for government for their response in dealing to this challenge," the spokesman said.
Despite the lifting of the hand baggage ban, BAA claims that Heathrow is continuing to experience "significant disruption to its operations", with passengers still being told that they will only be permitted to carry essential items such as travel documents onto the plane's cabin in transparent plastic bags.
Earlier reports had suggested that BAA had ordered airlines to cut the number of flights departing from Heathrow by 20 per cent today in a bid to ease congestion at the airport.
Flights from Heathrow were reduced by 30 per cent yesterday as BAA and airlines struggled to cope with tightened security measures introduced in the wake of the alleged terror plot to blow up transatlantic airliners, which was foiled by police last week.
British Airways (BA) has said that it has cancelled 39 short haul and five long haul flights from Heathrow today in the wake of the ongoing additional security measures.
The airline said that it expected to operate a full European and long haul schedule from Gatwick, where hand luggage restrictions also remain in place. However all 26 domestic flights due to depart from the airport have been cancelled, with the exclusion of flights from Jersey.
BAA's announcement that it will not be in a position to implement the lifted ban on hand luggage until tomorrow is unlikely to be welcomed by Britain's airlines, many of whom have been critical of the airport operator in its handling of the tightened security arrangements.