The story has been well-reported: some passengers felt that two young men booked on the flight were behaving oddly, so refused to fly. Their concerns ricocheted around the plane as it stood on the apron; passengers disembarked, and they refused to fly until the men were thrown off the flight.

The Spanish police duly boarded the plane, arrested the men, and detained them. Having ascertained that they posed no threat, they were put on a later flight.

A little probing around the story makes worrying reading. One passenger tells the BBC website: "we got on the plane and we boarded and it became apparent after we were already supposed to be flying that several of the passengers had refused to board the craft. It became apparent that the reason that some of the people didn't board the plane was because somebody had overheard the gentlemen in question speaking - I think it was Arabic."

Rightly, Birmingham MP Khalid Mahmood has slammed the vigilante attitude of the passengers - and the airline for handling the situation so badly. Thumbs up also to British Airline Pilots' Association whose spokesperson David Reynolds says: "Clearly, we can't have a situation where one passenger decides that another passenger isn't going to fly".

Increasing security on flights must mean making everyone safe, and making them feel safe. Alienating and inconveniencing people based on the colour of their skin, and not sound intelligence, will not them feel safe.

It is not a difficult notion to grasp that speaking Arabic - or any other foreign language - does not a terrorist make. But more than that, we need to understand why passengers believe that they are more effective at policing aircraft than those professionals trained to do it. Is it just plain, up-front prejudice, or is there a creeping cynicism about airport security? Either is very worrying, and almost certainly won't improve aircraft security. Good, old-fashioned solidarity is an essential element of aircraft security.

So the appalling events on the flight from Spain tie into another hot political issue: passenger profiling. Some budget airlines known for their sharp practice have raised the issue last week. Why search everybody getting on a flight, they ask - though a series of carefully coded messages - when terrorists are generally Asian? The former head of the Metropolitan Police, John Stevens, is more explicit: "I'm a white 62-year-old 6ft 4in suit-wearing ex-cop - I fly often, but do I really fit the profile of suicide bomber? Does the young mum with three tots? The gay couple, the rugby team, the middle-aged businessman?"

He believes that "young Muslim men" should be the subject of additional checks at airports. Thousands of Labour activists have been rightly angered by his comments.

Clearly we face a real, genuine and unprecedented threat of terrorism in the UK. There are four main reasons why passenger profiling is a bad idea.

First is that it is easy to circumvent - at least according to Jane's Defence Review who tend to know about these things. Ultimately, its efficacy is for experts to discuss.

Second, passenger profiling makes assumptions about people based on their appearance. Surely a progressive country will not allow itself to be scared back decades in the fight against stereotyping and prejudice. The Labour Party should continue to fight against us making assumptions about people based on how they look.

Third, the ideas behind passenger profiling may lead to unintended consequences. There are a handful of people in the UK who may be terrorists - but there are millions of young Muslim men who are not terrorists. The leap from believing that all terrorists are young Muslim men to believing that all young Muslim men are terrorists is regrettably not a very great leap at all.

Fourth, passenger profiling hands one to the terrorists. It's easy to jump on the bandwagon of saying in response to any proposal that does not meet with your approval that `this is just what the terrorists want', but here this is a justified claim. Dividing our `safe' passengers from `dangerous' passengers is clearly a victory to those that would disrupt our multi-cultural community, to those terrorists that believe that Muslims and non-Muslims should not live together. Where there is relative harmony, they would bring absolute discord; where there is equality before the law, they would bring distinction. We should not aid that and we must resist it.

Increased airport security for everyone may be inconvenient - but it is justified. Young Muslim men are the victims of terrorists too, and deserve no more or less inconvenience than every other category of victim. So we'll all just have to get the airport a bit earlier and queue up for security checking together.

We need fewer assumptions about people; instead, we need hard evidence. Instead of categorising people into a potential terrorist or not, we need to categorise intelligence. So let's hear less about passenger profiling people and more about intelligence profiling.