An intending traveller to the US could be branded a security threat without right of appeal under new plans, writes Ian Kilroy in Boston

In Steven Spielberg's science fiction film Minority Report suspects are arrested before they commit a crime. A "pre-crime" police unit apprehends them based on the predictions of clairvoyants who can apparently see crimes to be committed in the future. People who have yet to do their wrongs are taken away. The authorities assume the information they act on is flawless.

It turns out to be anything but.

Today, something like this sci-fi scenario is becoming reality. Based on who you might turn out to be, the US wants a lot of your personal details before you arrive. The EU, among others, isn't too happy with the proposal.

The Department of Homeland Security says it needs to introduce the passenger screening system for everyone travelling to or within the US.

The idea is to delve into private, commercial and government records to compile profiles of every US-bound traveller, instantly colour-code them as green, yellow or red security threats and draw up a no-fly list of everybody who is considered potentially dangerous.

Not only does the plan appear to disregard EU privacy laws, but also it may not prove effective in doing what it's designed to do: stop another September 11th.

The United States' current scheme, the Computer Assisted Passenger Pre-Screening System (CAPPS), was introduced in 1996, after TWA flight 800 went down over Long Island Sound, killing 230 people.

Before it was learned that the tragedy had nothing to do with terrorism, CAPPS had been implemented by the Clinton administration. The system was supposed to single out potential terrorists for increased vetting before they boarded flights. Passengers who bought one-way tickets, checked in without baggage or paid for flights in cash were flagged by the original CAPPS system as potential threats.

Now Homeland Security's Transportation Security Administration wants to go a lot further. CAPPS II, as the proposed new system is known, would be the largest surveillance system ever used on civilian populations, what the American Civil Liberties Union has dubbed a "surveillance monster that won't make anyone safer".

The idea is that each airline will supply the Transportation Security Administration with the name, address, date of birth and telephone number of each prospective passenger. A computer will then use data-mining software to cross-reference that information with computerised records. Next your level of security risk will be determined, and finally your passenger profile - with potentially everything from your on-board food preferences and travel companions to your credit-card details and employment record - will be stored for years to come.

For CAPPS II to work, a huge amount of private information will be needed about each passenger; otherwise it will be impossible to build a profile of each individual. Of the 39 pieces of information that the US wants on each traveller, only 19 are permitted to be disclosed under EU privacy laws.

Airlines that co-operate with the US will be breaking EU law. Airlines that refuse to gather intelligence will be denied US landing rights. The EU and US are at loggerheads, and the airlines are caught uncomfortably in the middle.

Critics of CAPPS II say that part of the problem is that private information is likely to be sold on to marketing interests by the companies that run the computerised reservation systems that airlines use for booking passengers. At least one of the four big reservation- system companies that the Transportation Security Administration plans to use to gather information has subsidiaries in the marketing world. The US has nothing like the data-protection legislation that exists in Europe, and it is likely that intimate information on private citizens would be sold on from company to company.

Another problem is that, as it stands, CAPPS II has no independent appeals procedure. If the system indicates you are a red, or high-risk, passenger due to faulty information (of which there is plenty) held on computer, or simply because it couldn't source enough information on you, then you could end up on a no-fly list. As appeals are up to the administration, with no independent adjudication, you could be left on that no-fly list with no recourse.

While negotiations continue between the EU and US, opposition to CAPPS II is mounting within the US. About 8,000 people have formally objected to the federal government about the plan, and at least one man is suing the government, saying curtailing his right to travel in any way is a challenge to his constitutional right to freedom of assembly.

But even Congress is wary when it come to CAPPS II. It has requested that the scheme not progress until issues of privacy and cost have been sufficiently examined. It seems Congress is beginning to have second thoughts about the free rein it has given the Bush administration since the September 11th attacks.

Other US groups that have not been too keen on the Homeland Security proposals are the Association of Corporate Travel Executives, an association for business travellers, and, as might be expected, the airline industry, which hardly needs anything that makes flying less attractive at the moment.

Advocates for CAPPS II counter criticism by pointing to the trade-off needed in civil liberties for increased security. Isn't it worth giving up a little privacy to ensure thousands don't die in another 9/11-style attack?

That argument is undermined by the ease of "identity theft". For a few hundred dollars a fake ID can be bought on the black market. It would not be too difficult for a terrorist to pass himself off as someone else, gain a green - or safe - passenger profile and so be subject to less stringent security checks. As for forging an identity, the Internet is flooded with the four essentials of any identity: name, date of birth, address and telephone number.

Still, the Department of Homeland Security plans to have CAPPS II up and running by next summer. Negotiations continue and the EU commissioner with responsibility for data protection, Frits Bolkestein, has managed to get some concessions - the US has watered down the length of time it wanted to keep each passenger profile from 50 years to seven, for example.

But the US administration is in bullish mood, and the Department of Homeland Security seems eager to push this through.

CAPPS II is a system terrorists will find a way to beat - and one that sacrifices much in civil liberties without having been proven effective. But its advocates do not consider these arguments convincing. Nor does the US seem concerned about the implications for the privacy laws of other nations.