A high-speed Eurostar train leaves the Channel tunnel near the Eurotunnel terminal of Coquelles near Calais, northern France.

Paris - Considering how close are Britain and France - the White Cliffs of Dover stand just 21 miles from Cap Gris Nez - you can fly to an implausible number of French airports from the UK. Even in the bleakness of December, before the ski season flights to Chambéry and Grenoble begin, I can count 18 destinations from London airports alone, from Bergerac to Tours.

Allow me to add the “Swiss” airport of Basel (deep inside French territory, connected to the rest of Switzerland only by a narrow umbilical known as the Route Douanière) and Geneva (the main airport for the French Alps). With a scattering of destinations such as Rennes, refreshingly served only from airports outside London, there are about two dozen alluring villes to which you can fly even in the lowest of seasons.

All of which presents a problem for Eurostar. Less than a year after the train operator started services through the Channel Tunnel from London to Paris and Brussels, an odd little airline called easyJet started. While Eurostar now dominates the market between the capitals of Britain, France and Belgium, it has always had a problem taking people further. The budget airlines have proved extremely successful in connecting airports across the UK with cities scattered across France, at fares that looked frankly unfeasible when Eurostar first put its business plan together.

Only one train connection a day between London and Nice (the 8.31am from St Pancras) can get you to the Côte d'Azur in under nine hours, while a dozen jets are lined up to get you there in two hours - with the added bonus that Nice airport is at the west end of the Promenade des Anglais. The train journey could be accelerated to eight hours if Eurostar ran a direct train, but the firm has correctly observed that this would constitute the fast track to penury.

Instead, Eurostar is looking at places that the planes can't reach. Its summer service between London and Avignon takes advantage of the fact that the former papal abode has only a tiny airport, whose terminal resembles a suburban garden centre, with only a handful of flights from the UK, using small planes. In contrast, Eurostar has the capacity to deliver 750 people - a couple of jumbo jets' worth - every Saturday afternoon from July to September, to the handsome Avignon Centre station a few minutes' walk from the Popes' Palace.

Tickets for the service went on sale December 11. But at the same time, an intriguing new departure is on offer. On Saturdays between 4 May and 29 June, a direct train will run between St Pancras and Aix-en-Provence, calling at Lyon and Avignon along the way.

Those of us who regard rail as the most civilised way to travel will celebrate the chance to travel from central London to the deep south of France. And the closer you look at the destinations, the more appealing they seem. Even though Lyon has plenty of flights from the UK, the airport for France's second city is inconveniently located at the far end of Europe's most expensive tram link. In contrast, the direct train is scheduled to take under five hours, arriving on the dot of one in the heartland of French gastronomy.

At Avignon, under six hours from London, the train serves the futuristic TGV station - which means connections to Nîmes and the south-west are easily available. And you can step off the train at Aix-en-Provence TGV just as the midday sun of the Midi is easing into another glorious afternoon.

Even better: the trains are being run at less than half capacity in order to avoid stressing the system; you are guaranteed room to move.

Aix and pains

That's the (very) good news. But there, on the opposite platform, the bad news is already backing up. First, look more closely at the departure and arrival times at St Pancras. Outbound, you have to check in by 6.47am; inbound, the train arrives at 10.39pm. These timings are feasible, if uncomfortable, for anyone residing in Zone 1 of the London Underground, but impossible for those travelling even from stations with a direct connection to St Pancras International, such as Leicester and Peterborough.

Next, where was that gare again? The person who named “Aix-en-Provence TGV” station evidently attended the Ryanair school of geography. The station is much closer to the Mediterranean (just five miles west) than it is to the famously landlocked city of Aix-en-Provence - a bus ride of 20 minutes or more away.

Homeward bound?

You finish a long, languid Provençal lunch, bid farewell to the deep south of France and flop into your half-empty train ready to snooze all the way to St Pancras. What could possibly go wrong? You'll find out at Lille, where everyone has to pile off the train for an astonishing 80 minutes to go through pre-tunnel security and British passport checks.

“We recognise it's not a perfect solution,” says a Eurostar spokeswoman. So will prospective travellers. I shall be waiting at 9am on Tuesday to buy my ticket, but booking the train only one way to “Aix”. I shall fly home from Marseille airport, itself only half an hour by bus from Aix, in about the length of time that the Eurostar passengers will spend in the draughty confines of Lille. A change isn't as good as a rest. - The Independent