Computer scientists in India say they have solved a mathematical problem that has eluded researchers for more than 2000 years.

The three-man team from the Indian Institute of Technology in Kanpur say they have devised a method that can accurately determine which numbers are prime numbers - divisible only by themselves or the number one.

The discovery is said to be significant because prime numbers hold the key to solving important mathematical problems.

Scientists have long worked to discover ways of accurately identifying prime numbers - one of the first was the ancient Greek mathematician, Eratosthenes.

From the newsroom of the BBC World Service