The body that regulates fertility treatment in the UK says it is only a matter of time before a ban on the use of frozen eggs is lifted.

Ruth Deech, head of the Human Fertilisation and Embryology Authority (HFEA), told the BBC that scientific evidence proving the practice was safe was inevitable.

She said: "Given how fast the science moves, it is a question of time. I have no doubt that sooner or later - I don't know when - the evidence will come that shows us it is the right time to go ahead."

A leading London fertility clinic will meet with the HFEA on Friday to ask for a change to the current regulations.

The Assisted Reproduction and Gynaecology Centre wants to use the technology to help recovering cancer patients to get pregnant.

At present, the HFEA allows women to have their eggs frozen, but it does not allow doctors to subsequently fertilise them - or even thaw them.

The HFEA says it is not yet convinced that the procedure would result in healthy babies, even though it has been carried out more than 30 times in countries such as Italy and the US.

The issue hit the headlines last month when a Belfast woman who had her eggs frozen while she underwent cancer treatment was told she was not legally allowed to try for a baby.

Carolyn Neill, 34, was told by doctors that radiotherapy was almost certain to render her infertile, but as she did not have a partner, she opted to store some unfertilised eggs for future use.

Now she has been declared free from cancer, she wants to start a family.

But Ms Neill even needs official permission to take her eggs abroad to a country which allows the procedure.

Her eggs are currently stored at the Assisted Reproduction and Gynaecology Centre, whose director, Dr Mohammed Taranissi, is battling for the procedure to be approved.

'Waste of time'

Ms Neill told the BBC: "I feel very cross. It should be down to Dr Taranissi and myself to discuss what we should do, not the government to have a law that is cut and dried.

"If you are allowed to do one stage, why not the end stage?

"I just felt it had been a waste of time, that hope was gone all of a sudden, but I know that Dr Taranissi and other clinics were fighting for the law to be changed."

But Ruth Deech, said: "We are worried that any child born from that treatment might not be healthy. We all remember Thalidomide. We must never have anything like that again."

The freezing service at Dr Taranissi's clinic costs �2,800 a year - the centre was given a licence to carry out the procedure last October.

The terms of the licence prohibit the thawing of the eggs or their fertilisation.

Dr Taranissi said: "The only reason to freeze eggs is for us in future treatment - so I don't quite understand the rationale behind this."

The Society for the Protection of the Unborn Child has condemned the award of the licence saying it opened a "Pandora's Box" which could lead to the commercialisation of test tube babies.