LONDON BRIEFING:PASSENGERS AWAITING the return of their bags from Heathrow's Terminal 5 can now while away the hours, or days, with an entertaining new online game.

Entitled "Wee Willie Walsh in Terminal Panic" - www.weewillie walsh.co.uk - it features a cartoon version of the British Airways chief executive, who battles killer trolleys in a desperate race to screen and load luggage on to conveyor belts. The aim of the game is to load the luggage before all the flights have left.

As the world now knows, the real life Willie Walsh lost the game. The £4.3 billion (€5.44 billion) state-of-the-art terminal, which took two decades to plan and build and was supposed to restore the reputation of Heathrow, has become a national embarrassment and international joke.

"You couldn't make it up" became the common refrain last week as the scale of the fiasco unfolded. Now, almost a week after it opened its doors to passengers, flights are still being cancelled at the new terminal at the rate of about 50 a day - more than 300 in total - as it struggles to cope with the backlog of baggage.

Although the queues that marred the first few days have now disappeared, so too has a mountain of luggage - as many as 28,000 bags at one stage, according to government figures.

Those bags are being re-screened manually and some, apparently, are being driven from Heathrow to Gatwick Airport, almost 50 miles, to go through security checks there. Now that definitely falls into the "you- couldn't-make it-up" category.

If the Harvard Business School is looking for a case study in how not to launch a multi-billion pound facility, it need look no further than T5. Despite months of planning, it descended into chaos within hours as a series of minor glitches combined to create chaos.

These "teething problems", as BA insisted on calling them, ranged from staff being delayed in the car parks and having to queue - up to 60 deep - to sign into the building. Once they did gain access, many appeared unable to find their way around the new terminal or were unable to log on to the computer system. Baggage handlers were sent one way, luggage another.

All these issues were, or should have been, under BA's control and should have been rehearsed again and again ahead of the launch. We can only imagine what would have happened had there been a serious problem, such as a terrorist threat or a thick blanket of fog.

Once the problems started, however, it became impossible to catch up. When a new wave of passengers descended on the terminal on that first afternoon last Thursday, the whole thing collapsed like a house of cards.

While Walsh himself has refused to resign over the debacle, it seems inevitable that heads will roll once blame is apportioned. Whatever he says now, Walsh's position will become less tenable the longer the chaos continues.

At this stage, it is impossible to say how many passengers will choose to avoid Heathrow in the future, whether or not the early problems are, as Walsh promises, swiftly resolved.

It is not just the reputation of BA - and airport operator BAA - that has been damaged by the T5 debacle. It is a serious embarrassment for Gordon Brown's government and has heightened fears that the 2012 Olympics could prove to be a disaster for Britain.

Preparations for the games have already got off to a sluggish start; those who fear the worst have only to point to the disaster of the Millennium Dome project.

According to some analysts' estimates, the affair could cost BA up to £50 million - and that does not include the potential loss of business that might result from the negative newspaper coverage and television footage broadcast around the world.

For the Los Angeles Times, T5 managed a near-impossible feat - making Los Angeles airport, regularly voted one of the world's worst, look cutting-edge. The Times of India was scathing, saying the "hubris" of BA and BAA "is tragically reminiscent of the proud boast put about by the British-owned White Star Line when it declared its luxury flagship, the Titanic, unsinkable."

T5 also provided fodder yesterday for April Fool's Day, with one newspaper correspondent - Polly Filler - reporting on plans to introduce a petting zoo at T5.

According to Filler, airport officials hope the zoo's introduction - which will cost about £500,000 a year - will help calm stressed passengers and entertain children.

Pets in pens at Heathrow? Not that's about as likely as Willie Walsh becoming the star of a computer game.

• Fiona Walsh writes for the Guardian newspaper in London