A woman who had her eggs frozen while she underwent cancer treatment has found she is not legally allowed to try for a baby.

Now a High Court challenge may be launched by a leading London fertility clinic in an attempt to change the rules.

Carolyn Neill, 34, from Belfast, 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.

However, while the government watchdog which regulates fertility treatment in the UK allows women to have their eggs frozen, it does not allow doctors to subsequently fertilise them - or even thaw them.

And Carolyn even needs official permission to take her eggs abroad to a country which allows the procedure.

The Human Fertilisation and Embryology Authority 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.

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

She told the BBC: "I feel very cross. It should be down to Dr Taranissi and myself to discuss what we should do, not the goverment 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."

Ruth Deech, who runs the HFEA, said: "We don't yet have the scientific evidence that the use of these thawed eggs is safe. We will not allow women to be experimented on."

"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.

'I don't understand'

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.

A spokesman said then: "I can see situations arising where the partner would have to use a surrogate mother to carry the frozen egg without the dead woman's consent."

He added that women would use the technology to delay having their babies until after the menopause, then using a surrogate mother.