Researchers said that a hair cream or a conditioner to reverse the graying of hair will hit markets by the next two years.

Dr. Bruno Bernard, head of the hair biology research team at beauty firm L’Oreal in Paris, said that hair turns grey when pigment producing cells called melanocytes, become flat or no longer work in a proper way.

He and his fellow workers also discovered that the enzyme known as TRP 2, which is found in the skin and defends it from losing its pigment, give the skin its color.

The researchers think that the same enzyme may be able to trigger the pigment cells in hair follicles and allow people to maintain their hair color for a long time, or even reverse the process.

“The hair whitening process is slow and progressive, so we can prevent it,” Dr. Bernard said.

The new research will come as a relief to the many Britons who often color their hair to hide the grey threads.

Approximately £206 million was spent in 2008 alone on hair-colouring ­products, despite lots of celebrities comprising TV ­presenter Phillip Schofield and actor George Clooney – who wear their grey with pride.

Nick Ede, a GMTV lifestyle specialist, said that the discovery was “really great”.

“This will be ¬welcomed with open arms. It will save a lot of people a lot of money and I think it will be very beneficial,” he added.

However Angela Marshall, an image consultant and the owner of Surrey-based Appearance Management thinks that the new conditioner may not be advantageous for everyone.

“It could be problematic for people with very dark hair as their eyebrows would probably still go grey and then their colourings would not match well. So treatment would probably be better for people with blonde hair where there would not be such a stark contrast,” she said.