It is hoped that the virus therapy treatment, killing tumours by infecting them with viruses like the common cold, could become a third pillar - alongside radiotherapy and chemotherapy - in the standard battle against cancer.

Dr Brian Patterson, a GP in Portglenone, said anything that could improve the lives of cancer sufferers must be welcomed.

He told the Belfast Telegraph: "We need to study the details of this and see exactly which types of cancer it deals with and also to see what the downsides are - because most medicines have some sorts of side effects.

"That said, however, anything that lengthens or improves the quality of life of people with cancer has to be welcomed."

Arlene Spiers, chief executive of the Ulster Cancer Foundation, said the charity was looking forward to the next stage of the trials.

"Rapid changes are occurring in cancer research, diagnosis, treatment and care and the need to develop new and innovative ways of approaching cancer issues is urgent," she said.

"UCF remains committed to driving forward high quality programmes of cancer research in both our local universities and news of this kind is very heartening indeed.

"We look forward to the next stage of these trials and the possibility of a new licensed treatment and a more positive outcome for cancer patients."

The trials are due to be led later this year by Leonard Seymour, Professor of Gene Therapy at Oxford University, who had been working in London and America.

He has been working with viruses that kill cancer cells while avoiding harming healthy tissue.

Prof Seymour's technique, which would be useful for secondary cancers, involves a "stealth virus", masked from the body's immune system with a "polymer coat", which could spread through the blood and reach tumours.

Preliminary research on mice has shown that the viruses work well on tumours which resist standard cancer drugs.

Two viruses are likely to be involved in the first clinical trials - adenovirus, which normally causes a cold-like illness, and vaccinia, which causes cowpox and is also used in the vaccine against smallpox.

Both will be disabled for safety to make them less pathogenic, but Prof Seymour eventually hopes to use natural viruses.

Several more years of trials will be needed, eventually using the polymer-coated viruses, before the therapy can be considered for use on the NHS.

It is hoped that they can eventually be used on all cancers.