Fear and flying: a not-so-brave new world of airport security comes into effect tomorrow

More hurdles and longer queues at airports, and the risk of a stranger breaking into your baggage: that is what 2003 holds for airline passengers.

As the New Year rush gets under way, stressed travellers must be prepared for yet tougher security measures. British passengers returning home from some popular holiday destinations will find much more stringent rules on the baggage they check into the aircraft hold.

Queues will be longer and tempers shorter as "100 per cent hold baggage screening" takes effect in Spain, Italy and the United States. British travellers boarding at American airports are being told: "Keep your luggage unlocked, or we may break it open."

Since the hijacks of 11 September 2001, airline passengers have become accustomed to rigorous checks of hand baggage. Now, because of fears that a suicide bomber could smuggle aboard a device in checked luggage, several countries are following Britain in insisting that every case is checked before being loaded into the aircraft hold. But there are sharp discrepancies in how the new systems will work; the US security agency is reserving the right to break into baggage to see what it contains.

Tomorrow, the US government's Transportation Security Administration (TSA) will introduce full screening as part of a $3bn (£1.8bn) enhancement of airline security. At some airports, this will take place before check-in, so the passenger will be present if a case needs to be opened. But elsewhere baggage will be examined after it has disappeared on the conveyor belt. The agency is telling visitors to America to "leave their checked bags unlocked, which will avoid the potential need to forcibly open bags that require further physical inspection".

The TSA says inspectors will open any luggage that sets off an automatic alarm or raises the concerns of security staff inspecting X-ray screens. Food or drink has a propensity to set off alarms, while books stacked together can look like explosives; "spread them out", the agency suggests.

If a checked bag is searched, a "Notification of Baggage Inspection" stating that the TSA is not liable for damage will be put inside. The case will then be sealed. "Our highly trained screeners will take great care to secure your bag for the rest of your trip", the TSA's website promises.

A senior source in a British airline called the scheme "a thieves' charter", adding: "It sounds like Christmas all over again for the criminal fraternity of Europe's baggage handling profession. They will have carte blanche to rifle through any luggage arriving from the US, knowing the blame for any missing valuables can be pinned on the Americans."

The new rules apply at all 429 commercial airports within the US. They do not affect most passengers flying from Britain to America. But they will apply to anyone with a connecting flight within or from the US, and on the return journey to the UK.

British Airways and Virgin Atlantic already run 100 per cent hold baggage inspection for their flights from America. If a suspicious bag is identified, the passenger is traced in the terminal and asked to unfasten it for inspection.

Virgin, which has 12 daily flights from America to London, is installing signs at US airport check-ins to warn customers about the new system. "We will advise passengers that if their cases are locked they may need to be broken open when they are not present," a spokeswoman said.

Jamie Bowden, a leading airline consultant, said the US move "goes against every piece of personal security advice that passengers have been given for decades, which is to keep possessions safe by locking luggage. The present screening arrangements work well in the UK. The world's airlines should be introducing a common system along British lines rather than the Americans going it alone."

The TSA is hoping to introduce a system of colour-coded plastic locks to be given to passengers; a red lock will be attached by the passenger, and if the bag is opened then security staff will replace it with a blue one. Until a workable system is introduced, airlines are likely to receive complaints from passengers who find their baggage has been interfered with.

Some industry figures have also raised the concern that the new regime could make life easier for drug smugglers, who – if caught – will insist the consignment was planted in their unsecured luggage.

Travel insurance companies could face increased claims, because their insistence that bags must be locked can no longer be enforced. Frances Tuke of the Association of British Travel Agents said: "We're unhappy about the risk to travellers' possessions. Travellers should call their insurance company before setting off to find out if they will be covered in the event that something goes missing."

Tomorrow also marks the introduction of 100 per cent screening in Spain, which could lead to long queues and delays for British travellers returning home. The country's leading airports – Alicante, Barcelona, Madrid, Malaga and Palma – will screen all hold baggage before check-in.

Securing the skies

This year has been a typical one for air crashes: 10 fatal accidents, killing a total of about 1,000 passengers. (More than one million people die each year worldwide in road accidents.) Unlike 2001, none of this year's crop of air disasters is believed to be the result of terrorism.

The death toll would have been much higher if the two anti-aircraft missiles fired last month at an Israeli charter jet at Mombasa had hit the plane. Air security experts believe that the threat from a terrorist lurking on an airport perimeter with a shoulder-launched missile, and a better aim, is high.

But an even bigger concern is that a suicide terrorist will place a bomb in checked luggage, destined for the aircraft hold. He or she may even smuggle in a device to trigger the explosion over a crowded area, such as the approach to Heathrow over central London.

Security experts once assumed that no terrorist wanted to die in an attack. But on 11 September 2001, 19 terrorists demonstrated their willingness to perish with their victims. So the aviation world is moving as quickly as it can towards the goal of screening every piece of checked luggage.

A long wish-list of security measures remains to be fulfilled, many of them described on the aviation website, www.AirSafe.com. Some are straightforward, such as banning "items that could be used in a defensive fashion by hijackers" – for instance, bullet-resistant vests. Others require substantial investment, including plans for an automatic pilot that overrides any flight path set to pass through a building.

Even more in the realm of science fiction is President Bush's desire for "technology to enable [air traffic] controllers to take over [a] distressed aircraft and land it by remote control".