The patent covers software buried deep inside a phone

The ruling overturns a refusal by the UK Intellectual Property Office to give the mobile phone firm a patent.

The case is being watched with interest because before now it was rarely possible to patent dedicated computer programs in Europe.

The UK IPO has launched an appeal to get guidance on the circumstances in which it can grant such patents.

Clear rules

In its original application Symbian wanted a patent on a specific way to structure and update the collection of small files, called a Dynamic Link Library, found in many modern operating systems.

Symbian issued a statement after the ruling which said: "Symbian is pleased with the ruling and feels strongly that this decision will strengthen the position of British technology companies in the global market."

In the UK it has typically been difficult for hi-tech firms to win patents on innovations because of the wording of the 1977 Patents Act and subsequent case law.

Explaining its decision, the UK IPO said it applied the standard test that has arisen out of intellectual property cases which have helped to separate genuine innovations from minor differences in programming.

Andrew Bartlett, deputy director of the UK IPO, said patents could be granted on computer programs albeit in a limited set of circumstances.

what we need is clarity on the law and we need to know the test to apply

Andrew Bartlett, UK IPO

"You are not prevented from getting a patent just because you are using material means that involve a computer program," he said.

For instance, he said, a novel anti-lock braking system for cars that used smart software to decide how to slow down a vehicle could win a patent even though it relied largely on a computer program.

"Where we have a bigger problem is where we have a pure program where there is no external effect," he added.

A complication has arisen in this case because although the initial application was refused in the UK, it was granted by the European Patent Office.

The rules governing what can be patented in the UK were broadly the same as those used by the European Patent Office, said Mr Bartlett.

"In most cases, the huge majority of cases, we will get the same result," he said.

But, he said, recent British case law had opened up a divide between the UK and Europe.

Mr Bartlett said the UK IPO would appeal to ensure that it understood the rules governing what can be patented.

"If a court tells us we should grant something that's fine," he said. "The judgements are binding on us and what we need is clarity on the law and we need to know the test to apply."