On the face of it, the island of Sark was as tranquil as ever yesterday. Visitors pottered around the car-free lanes and explored the rocky coastline while the locals seemed to get on with life as slowly and steadily as they always have.

But this was no ordinary day. Hundreds of miles away on the mainland the Queen was giving royal assent to fundamental reform of the island's constitution, until now a bastion of feudalism in the west.

For 400 years the majority of those who sit in Sark's parliament, the Chief Pleas, have not been elected but are entitled to a seat because they own land. Islanders have also been subservient to the seigneur, effectively the lord of Sark, who has his own private army, who until recently took a handsome cut whenever property was bought and sold - and who was also entitled to a chicken a year from his "subjects".

No wonder when word from London finally reached Sark that Lieutenant Colonel Reg Guille, who as "seneschal" is the island's judge and presides over its parliament, described it as a "momentous" day. "It will see huge changes to our judiciary and government, making both more modern," he added. But he wanted island life to go on as normal: "It's a very quiet and peaceful place; we are a self-sufficient, close-knit community and we like to get on with life away from the public eye."

There are two main reasons, or three really, for the Reform (Sark) Law 2008. Firstly, more than 30 years ago Sark signed up to the European convention on human rights. It seemed a good idea until islanders realised that feudalism did not sit well with human rights.

The second and third reasons are the billionaire Barclay brothers, Sir David and Sir Frederick, owners of the Daily Telegraph and residents of a mock gothic castle on Brecqhou, a rocky island off Sark which is subject to its laws. They have led the fight for feudalism to be scrapped, claiming it is unfair and unjust. Their capitalist philosophy also makes them deeply opposed to handing over any cash to an island lord.

But not all are in favour of change. The philosophy of the current seigneur, Michael Beaumont, is: "If it ain't broke, don't fix it." As the decision came through yesterday, he was unavailable as he was riding his bicycle around the island.

His view is shared by many on Sark for whom the move towards democracy is proving painful. Phil Falle, a local journalist, said the atmosphere at meetings of the Chief Pleas had been "terrible" of late, adding: "The island seems to be splitting into two camps, those who support the Barclays and those who do not."

As well as pushing for democracy, the Barclays and their people have been buying up land and hotels. Some traditionalists fear they are turning the place into a holiday resort for the rich - and believe the new system of government may make it easier for them. On the other hand, supporters of the brothers argue that they are creating jobs, especially for young people who would otherwise leave.

Sark's elections take place in December and the new parliament is due to begin work in the new year. Unless, that is, legal wrangling halts the elections. Even ahead of the privy council's decision, the Barclays launched judicial review proceedings. They feel the reforms do not go far enough as, although members of the Chief Pleas will be elected, the seigneur and the seneschal will hang on to some of their powers in the parliament and the judicial system.

David Barclay, who rarely gives interviews, phoned the Guardian to express his concern such figures would still have important and unelected roles. "We are pushing for full democracy," he said. He also criticised Jack Straw, the justice secretary, for not intervening and pushing for stronger reforms on Sark. "I think this is an embarrassment for him," he said. It appears the fight for democracy on Sark still has a little way to go.

Backstory

Lorries and cars are banned on the Avenue, Sark's main street. The 600 residents move goods by tractor and travel around the three-mile-long island on horse-drawn cart, bicycle or foot. Sark is neither part of the UK, nor a sovereign state. Elizabeth I made the island a "noble fief" to be held in perpetuity by the first seigneur and his heirs. He split the island into the 40 tenements - chunks of land - that remain today. In return he had to defend the island against the French. Forty men still carry muskets. Over the years the seigneur's rights have been many and varied. He has had the right to keep the island's only pigeons and unspayed female dogs - and anything washed up on its shores. He has the front pew in the church - and other members of the congregation have had to pay 2p a year in pew rent.