The Biotechnology Research Council has made �8m available to help search for the next generation of medicines.

And the British Association science festival in Sheffield heard on Wednesday that the garden may be one of the best places to start that search.

The medicinal properties of plants are well known. Poppy extracts produce the pain relievers codeine and morphine while a compound from foxgloves is used as a heart medicine.

However, the exact chemistry of many plants - such as clover - that have been used for years to treat diseases ranging from coughs and colds to cancer is unknown.

The Institute of Grassland and Environmental Research in Aberystwyth is conducting trials to try to discover exactly what makes these plants so valuable to medicine.

Scientists at the institute are testing hundreds of British wild and garden plants with the aim of exploiting each plant's potential as a new drug.

Processing compounds

Dr Robert Nash, of Molecular Nature, a company which is working with the institute, said: "We are particularly interested in finding plants which could be easily cultivated for production of any valuable chemical we found."

To identify any chemicals scientists must first prepare a liquid plant extract.

Scientists test the chemistry of plant extracts

Further processing separates the individual compounds and after a chemical fingerprinting technique verifies whether the compound is new, its structure is determined.

One source of inspiration is Taxol - an anti-cancer drug isolated from the Pacific yew tree in 1971.

Dr John Wilkinson, of Middlesex University, said: "Everyone wants to go to the rainforest to find something really exotic but in actual fact in the UK we have got about 2,500 species and some of those have been studied, but there is a whole load of stuff that has not been.

"I think they will discover some new, interesting things and it will probably be good for the British economy as well."

The industry is already underway. Daffodil crops are now grown in East Anglia as a drug from the bulb can be used to treat Alzheimer's disease.