Scientists have turned their backs on technology to find a helping hand in the surgeon's scalpel.

Botanists at the Millennium Seed Bank project are surrounded with sophisticated equipment costing millions of pounds.

But no machine can replace their handiwork.

Using a scalpel and a pair of fine forceps, a team-of-three spends hours making cuts in scores of tiny seeds at the £80 million project at Wakehurst Place, near Ardingly.

Dr Robin Probert, head of training and technology, said: "These seeds are just like specks of dust. It would be impossible to automate this type of work.

"Any mistake could damage the embryo inside."

The scientists slit the seeds to remove a small part of their hard coating and reveal the embryo.

The experiments have proved slit seeds, particularly those of a tropical grass from Burkina Faso, West Africa, are more likely to germinate.

In the wild, the seeds are designed to remain dormant for years and only germinate when the right environmental trigger occurs.

Dr Probert said: "We don't know what that trigger is but by slitting the seeds we trick them by disrupting their coating and they germinate.

"The procedure lets the embryo escape from its straight jacket."

Hannah Davies, 23, a Cambridge University graduate who joined the international project in January, is one of the botanists to have mastered the precise skill.

She slits batches of 25 seeds on petri dishes every day.

Unsteady hands are useless, as one slip can lead to the embryo inside being damaged, making the seed a dud.

She said: "My hand is certainly a lot steadier than when I started here and I've definitely got quicker at doing the process.

"The seeds are really tiny so we have to carry the work out under a binocular microscope."

Any frustration with having to perform the detailed procedure is rewarded with the results. Most of the slit seeds germinate, while few of those left alone ever sprout.

Hannah said: "It's tricky, but it works."

The seed bank project, part of the Royal Botanic Gardens Kew, aims to collect seeds from 24,000 plant species by 2010 as a safeguard against extinction. About 6,000 types have so far been collected and stored in the vaults.

A spokesman said: "The seed bank scientists must ensure they know how to make the seeds germinate when needed, otherwise it is not conservation, but simply storing seeds.

"It's good to know there are some areas of science where humans are still better than machines."