For a couple of weeks a year, a select few British lawyers become the envy of their peers. Instead of struggling down the Strand to argue cases before unsympathetic judges, they sit as judges themselves – indeed, as no less than a court of appeal.

The fees they earn are no more than they would get as part-time judges in England, but the expenses are generous and the surroundings superb. The only downside, it strikes me, is that they must apply the laws of a territory that has kept its own legal system for more than 800 years.

With no law school of its own, it treats as authoritative a textbook first published more than 430 years ago – a work in which the author was himself commenting, at least in part, on law first collated some three centuries earlier still. That territory is Jersey.

‘It’s a highly desirable billet,’ says Michael Beloff QC, a leading barrister and, after 12 years’ service on the Jersey Court of Appeal, its senior ‘ordinary’ justice. ‘I like judging and Jersey law is very interesting.’

Jersey picks its appeal judges from the very brightest members of the Scottish and English bars. Those who have declined a full-time judicial appointment elsewhere, such as Beloff and Jonathan Sumption QC, can stay members of the court until they are 70. Others, such as Lord Hoffmann, served for only a few years before embarking on a judicial career in the UK.

The court sits for about seven or eight weeks a year, with each of the dozen judges spending a week or two on the island.

How, though, do they cope with Jersey law? ‘You have to pick it up,’ says Beloff. Like all judges, they rely on the bar – ‘its best members are excellent,’ says Beloff – and there are commentaries and cases to read.

Scottish judges and those who studied in South Africa – whose legal systems are based on Roman ‘civil’ law – may find this easier than those brought up in a common law country.

That is not to say that the common law has not lapped at Jersey’s shores. ‘The Channel Islands – like Scotland to a certain extent and other smaller jurisdictions where there is a large jurisdiction on the periphery – are constantly trying to preserve customary law and civil law influences from the incursions of English law,’ says Sir Philip Bailhache, the Bailiff of Jersey and hence the dependency’s senior full-time judge.

Torts, administrative law and criminal law are very much influenced by common law in Jersey, he tells me. ‘But succession and property are still heavily influenced by the customary law and by the civil law.’

Acting as devil’s advocate, I ask the Bailiff why Jersey would want to keep its customary laws.

‘You speak with the confident assumption that everything in English law is better than the law of any other jurisdiction,’ he tells me. ‘And that’s an attitude, if I may respectfully say so, with which we are very familiar.’

For example, Jersey has recently considered whether to bring its laws of succession into line with those in England and Wales.

‘We have a concept which goes back many hundreds of years called légitime, under which a testator is obliged to leave a percentage of his moveable estate to his widow and children,’ the Bailiff says. Only a third of his personal property can be disposed of by will.

Those who wanted to abolish légitime argued that English law was much better because people were free to deal with their property as they wished, subject only to a claim by dependants.

But the Bailiff disagrees: ‘I suspect that this testamentary freedom in England works great injustice because most people would find it much too expensive to ask a court to remake the will.’

And there was little the English courts could do if a man left all his money to the daughter who had been ‘cosying up’ to him in the last months of his life. ‘In Jersey, although it’s a brutally simple system, a testator can’t do that,’ he says. ‘The result is that the black sheep of the family and the doting daughter are both equally entitled to share in the parents’ estate. I think that this leads to social harmony. It’s a better system than the English system and I don’t want to change it.’

What Sir Philip Bailhache has changed since becoming Bailiff in 1995 is to make Jersey law much more accessible online – although access to recent judgments requires prior registration. He also founded and edits the country’s law review.

For now though, he is celebrating the contribution to Jersey law made by the 60 or so lawyers and judges who have served on the Jersey Court of Appeal since it was set up in 1961. The Bailiff was in London last month to host a dinner for more than 40 surviving members of the court.

‘It’s very difficult in a small jurisdiction of 100,000 people, where there are a limited number of cases coming before the courts, to preserve the integrity of a legal system which is entirely distinct from the legal system of England and Wales,’ he says.

‘The Jersey Court of Appeal has made an enormous contribution in that respect. Because they are top-rate lawyers, the judges have been able to set aside their training as English lawyers to look at the principles. They have developed those principles to deliver justice in the cases before them.’

And they have enjoyed a week or two in the sun.