Attempts to control the amount of alcohol available on Brighton and Hove's city centre streets have been blown out of the water by a court ruling in favour of supermarket Tesco. So what good are well-intentioned controls if they can be brushed aside so easily?

When you are a town with a large number of drinking establishments, there is always a danger the hedonism could spiral out of control.

It is something Brighton and Hove City Council is acutely aware of – and has won plaudits for managing.

Nightlife is hugely valuable to the city's economy, as part of the massive tourism sector that employs thousands, but it holds the constant danger of dragging down the city's reputation.

There is a delicate balance which, for the most part, is maintained by a well organised combination of work by the council's licensing officials, Sussex Police and several other groups.

But from time to time it does go wrong, most visibly in the overspills into alcohol-fuelled violence in and around West Street, which have regularly earned it the unwanted tag of Sussex's worst road.

It was a desire to keep these problems, as well as the underlying issues of alcoholism, homelessness and the knock-on social troubles, that led the council to implement its Cumulative Impact Zone last year.

The idea was simple. An area would be created around the city centre, and including St James's Street, where there would effectively be a cap on the number of outlets able to sell alcohol.

It was the council's way of saying enough is enough, we do not want, or need, any more alcohol being sold.

It meant that in future their licensing panel would be legally able to turn down future applications from shops, bars or restaurants wanting to serve alcoholic drinks in that area on the basis they would add to the overall impact which was already as much as they were happy with.

It was a well intentioned and common sense move backed by many residents – including those around St James's Street who were fighting to transform its reputation as a hangout for street-drinkers.

However, it now appears the plan could have been rendered impotent after it was defeated in court at the first time of asking.

Supermarket giant Tesco enjoyed a legal victory over the council this week after appealing against a decision to ban it from selling alcohol in a new Tesco Express at the corner of St James's Street and Dorset Gardens.

The council turned down the licence on grounds it would be too much for the cumulative impact zone, but the corporation successfully argued they could not be blamed for problems in the area.

That argument has set alarm bells ringing. Magistrates have made clear they intend to consider all cases on their relative merits but it seems Tesco have found a legal blueprint others could follow with ease.

What is now to stop any business the council decree to be an unwelcome addition to existing problems from turning around and saying they are not at fault?

Simon Burgess, chairman of the St James's Area Action Group, said: "It's hard to know where this leaves us, it is worrying to say the least.

"Residents and businesses here are so determined to turn this area around and part of that has been to tackle issues of street-drinking and antisocial behaviour.

"The cumulative action zone was exactly what we needed and has been part of real moves forward. Now we just don't know.

"The last thing we need is another alcohol outlet, especially one where drinks will be so readily available and cheap."

Councillor Carol Theobald, chairwoman of the council's licensing committee, admitted there was now uncertainty over the cumulative impact zone.

She said: "We hope this won't open the flood gates. The cumulative impact zones have worked well so far. They have enabled us to turn some licences down or force conditions on others.

"I don't think this will happen every time."

Perhaps of more concern will be the issue of whether Tesco were right in their assertion their licence would not lead to an overall worsening.

Some residents argue they were wrong.

Jon Barrenechea said: "What makes it a bigger concern is that we know Tesco discount their alcohol. We have a street-drinking problem in this area and cheap alcohol will worsen that.

"It's inevitable that other off licences and shops will then compete with them on price. There is a safety and well-being in the community issue here."

Tesco has insisted its store will not have a negative impact in the area.

A spokesman said: "We have got very stringent procedures in place to sell alcohol. Staff go through a lot of training around alcohol sales.

We take these things very seriously."