Roman Polanski’s escape route is a ski-lift to France

Switzerland's justice minister has said he is unlikely to appeal the granting of bail to Roman Polanski, who has been fighting his extradition to the United States on underage sex charges ever since he was picked up at Zurich airport by the Swiss authorities on September 26.

The news comes despite expressions of surprise from lawyers who point to the film director's previous form. Polanski fled Los Angeles for France in 1978, fearing a Californian judge would not honour the terms of his plea bargain following his admission of unlawful sexual intercourse with 13-year-old Samantha Geimer.

Polanski might have an hour before police responded to an alert from his tag

So, given his record of flight, what are the 76-year-old's chances should he decide to make a break for the border with France, whose president has expressed support for him and which is under no obligation to extradite its citizens to the United States?

Polanski has offered his Paris apartment to meet the bail of £2.7m granted this week. Under the terms of the bail offer, he is to surrender his passport and be placed under house arrest in his chalet in the luxury ski resort of Gstaad, tantalisingly close to the French border. Unfortunately for the director, he will be electronically tagged; if he attempts to leave his home, an alarm will alert police.

But how effective is electronic tagging? A three-year trial of the technology in Switzerland which ended in 2002 found that 16,000 alarms were set off - that's 14 per day. Given the frequency of these alerts, it is questionable exactly how quickly police would be likely to respond to one being tripped in Gstaad.

Perhaps Polanski would have an hour before Swiss police responded to an alert from his electronic tag? Along mountain roads, the 44-mile journey to Chatel across the French border would take approximately 1hr 20mins. But passport checks at the border - Switzerland is not an EU member - mean that Polanski would have to take his chances hiding in the boot of a car, which would highly risky both for the director and his accomplice.

But there are other, more surreptitious options. Hot-air ballooning is a popular