By now, everyone living in the northern half of Britain must be fed up with the performance of Eurostar. Long before the Channel Tunnel opened in 1994, travellers were promised direct trains from Berwick to Brussels and from Preston to Paris. Because the rolling stock was not ready (and still isn't), a solution was found: special trains from the North direct to Waterloo, for a quick change to Brussels or Paris.

We have revealed in these pages how underpopulated these services were - mainly because arcane regulations meant they could not carry people who wanted to go only as far as London.

Rather than try to change these rules, so that potential passengers were actually allowed to catch the trains, Eurostar has opted to cancel the special links. Now, Europe-bound passengers from Edinburgh, for example, must travel on ordinary trains as far as Kings Cross. Then they are supposed to use the Underground even though the obvious route - using the Bakerloo Line - is closed. London's cabbies must be delighted, as well as airlines flying to Paris and Brussels from regional airports.

Eurostar portrays the change as an improvement, pointing to a much wider choice of trains, and the prospect of travelling on Sundays. And some domestic rail users could benefit - though since the following wheeze involves bending rules, surely no reader of this column would be so unscrupulous as to try it?

To sweeten the regional downgrade, Eurostar has negotiated special fares on InterCity West Coast and Great North Eastern Railways. To qualify for a pounds 30 return fare from Glasgow to London, free of the usual low-fare advance purchase restrictions, all you need do is show an onward Eurostar ticket from Waterloo to the Continent.

It does not take a huge intellectual leap to realise that anyone in possession of a full-fare, refundable Eurostar ticket can qualify for cut-price travel between Scotland and London. You show the ticket at Glasgow Central station to buy your cheap trip to London, then hand in the Euroticket for a full refund.

If premeditated, this sort of behaviour breaks the rules. But suppose a mobile phone user (of whom there seem to be hundreds aboard every train these days) learns en route of a good reason why he or she should not continue with the European portion of the trip.

The passenger is surely not going to be asked to pay the full fare, even in the post-privatisation railway wonderland? Legal counsel would be appreciated.

No subterfuge is needed for the next top tip - just being born on the right day. The US airline Reno Air is giving upgrades to first class to any economy passenger who can prove it is their birthday. Annoyingly, this option applies only to those born in the first half of the year; it expires on 1 July.