Today, the man who discovered DNA fingerprinting underlines the importance of allowing academics to conduct “curiosity-driven” research.

A quarter of a century ago, Professor Sir Alec Jeffreys, now 59, stumbled across the groundbreaking development in a “eureka” moment.

At 9.05am on September 10, 1984, he realised that variable patterns in the structure of DNA could be used to distinguish one person from another. The technique led to the development of DNA fingerprinting, used to solve a range of crimes.

It has also been developed to help solve unanswered questions and disputes over personal identity, paternity, immigration, conservation and cloning.

Leicester University, where Sir Alec has worked for the past 32 years, will today mark the occasion with a Darwin/DNA Day featuring public lectures and discussion forums, and schools outreach and social programmes.

Professor Jeffreys said “blue skies” research, which led to discoveries such as his own, was “the ultimate engine of all scientific and technological evolution”, and warned: “You lose that at your peril”.

Sir Alec said attempts to set too many priorities and strategies in research led to “factory science” that worked towards predictable outcomes.

He said: “I am saying you have to have a mixed economy. You don’t have to put all your eggs into this great common basket that will deliver answers to questions that you can define, because the far more exciting thing is that it delivers questions that you never knew existed -- and that to me is infinitely more valuable because that sets the future agenda.”

The DNA fingerprinting technique has now been developed even further.

Dr John Bond, Scientific Support Manager at Northamptonshire Police and Honorary Research Fellow at the University of Leicester Forensic Research Centre, has developed a method that allows scientists to “visualise fingerprints” on metal even after they have been removed.

If a fingerprint has been deposited on a small calibre metal cartridge case before it is fired, the technique can enhance the print after firing.

This means it is possible to trace the person who loaded the gun, and it is even hoped the technique could be adapted for use on metal shrapnel from exploded bombs.

The technique was cited by Time Magazine as one of the top 50 inventions of 2008.

Professor Jeffreys said he remains excited about the potential of science to reveal the unknown.

Asked what discovery he would be most excited to see in the next 25 years, he replied: “No-brainer. Extra-terrestrial life. I would love to see that before I die.”

Sir Alec’s interest in science started when he received a chemistry set as a boy.

He was educated at the University of Oxford and stumbled across his discovery during other research into genetics.

Sir Alec and his team were involved in much of the early casework, and the scientist himself helped work on the first immigration case resolved by DNA as well as the first paternity dispute and the first murder investigation.

Sir Alec has received widespread recognition, becoming an honorary freeman of the City of Leicester in November 1992.

He also received a knighthood for services to science and technology, election to the Royal Society and several scientific awards.

But despite his “celebrity” status the scientist still insists on doing his own research, refusing to move into management. He now also enjoys raising awareness of and interest in scientific discovery by giving public lectures and visiting schools.

He said: “It is a huge privilege to be able to go out and give these talks, and you can see the excitement that can be generated.”