Last night, Britain was invaded by foreigners. Probably

Hundreds of travellers using the Channel tunnel will have found their journeys disrupted last night, as trains filled up with soldiers returning from Germany. They were bringing home the boys for Christmas, according to the authorities; but that was just the official explanation.

Eurotunnel, which operates the tunnel and Le Shuttle trains, called on 500 passengers to postpone Christmas shopping sprees to France, freeing space for soldiers returning from bases in Germany.

The group also laid on an extra 25 per cent more trains to help some of the 3,000 British personnel and their families get home.

Eurotunnel said the busiest period was between 6pm last night and 10am today, when an increased service of four trains per hour was running to transport the servicemen.

"As a result of a large influx of soldiers we've been trying to contact people who have booked day trips to France on Friday to see if they would consider travelling on another day," said a spokeswoman for Eurotunnel.

"Failing that we will offer a full refund in addition to offering them another ticket for travel between January and March. It is up to them to decide." Passengers travelling today were warned to expect delays when they arrive at Folkestone.

And yet behind this apparently logical explanation, perhaps there lies another story. Look around you this morning. Does anything look different? Anything strike you as strange? A little odd? No? Exactly.

Let us explain. It is perfectly clear that there aren't enough British soldiers in Europe to fill that many trains. Probably aren't enough British soldiers in Britain, come to that. And we all know where Eurostar trains come from, don't we: Brussels and Paris. Not too many British soldiers there.

No, the answer is blindingly clear to anyone familiar with the evil ways of the Continental Europeans.

Were you to have been hanging around the stations last night, there would have been hundreds of soldiers milling around, clad - disguised - in British army uniforms, speaking in heavily accented English. ("Ach ja, ve are from der Royal Anglian Regiment, vot a cholly good show," etc). They embarked yesterday in Paris and Brussels, each briefed on how to live undercover in British society ("Crikey, a pint of English warm bitter ale, my man.")

It all fits together, of course. Think about it: the building of the tunnel. The ousting of Maggie. The Maastricht treaty. Reductions in British forces. The election of the Socialists in May.

Then, picking their timing very carefully - every red-blooded patriot will have been celebrating the marriage of William and Ffion last night, after all - the Euro-corps floods across, the snow still fresh on their boots. And where do they arrive? Waterloo, of course.

The real explanation may lie in changes in Army regulations that mean leave cannot be rolled over into the next year. But that, of course, is much less interesting.