This comes in the wake of US findings linking another widely-used combination to an increased risk of heart disease, cancer and stroke.

Experts fear that many women may be confused by conflicting messages about HRT and abandon it altogether.

Hundreds of thousands of women in the UK use HRT to relieve menopausal and post-menopausal symptoms.

It can help reduce the incidence of hot flushes and sweating, as well as protect bone density, so reducing the chances of osteoporosis later in life.

The latest study, carried out by researchers at the University of Sheffield and John Radcliffe Hospital in Oxford, looked at a combination of oestrogen and progestogen, marketed in the UK under the name Kliofem.

This is not the same combination studied in the US trial.

We have to explain to women that taking any type of HRT is likely to carry risks, while making them aware of the considerable benefits involved as well

Mr Malcolm Whitehead, King's College Hospital

It looked at the progress of more than 500 women over a period of five years.

None of the women in the study develop endometrial cancer - which affects the lining of the womb, or even showed signs of precancerous cell changes in that area.

A few women who showed signs of these changes prior to the start of the study were checked again at the end - and no sign of the problem could be found.

The researchers believe that women on this type of HRT are better protected against endometrial cancer than those taking no HRT at all.

Risk balance

Malcolm Whitehead, consultant at the menopause clinic at King's College Hospital in London, acknowledged that many women were still nervous about potential health risks of taking HRT.

And he said that despite the latest positive results, published in the British Medical Journal, there was still uncertainty over the health consequences of taking newer HRT combinations over the long term.

He said: "Nothing in life is completely without risk - we have to explain to women that taking any type of HRT is likely to carry risks, while making them aware of the considerable benefits involved as well.

"What we need now is the pharmaceutical companies to organise long-term trials in various combinations of HRT.

"If they don't do these studies, use of HRT is going to diminish gradually because women will be anxious about it."

US trial

The US study involved a combination of hormone which is not available in the UK, although a similar drug called Premique is currently the market leader, with 300,000 users.

The trial was halted early because the researchers said there was clear evidence that the US combination was increasing the risk of heart disease, stroke and cancer - an unjustifiable risk to women.

However, Mr Whitehead said that the evidence was not quite clear-cut - in particular, it was possible that many of those who suffered heart problems may have had other risk factors such as high cholesterol levels or obesity.