A Church of England curate today won the first stage in her battle to force police to investigate a late abortion on a woman who did not want to have a baby with a cleft palate.

The Rev Joanna Jepson, curate of St Michael's church in Chester, was given approval for a legal action against Paul West, chief constable of West Mercia constabulary, over his decision not to bring charges.

She says he sanctioned an illegal abortion by failing to investigate a pregnancy termination after the six month legal limit.

The unnamed woman, from Herefordshire, chose to abort the foetus after finding out it would be born with a cleft lip and palate - although the pregnancy was past 24 weeks. After this time an abortion can only be carried out if there is a risk of serious handicap.

Ms Jepson believes that a cleft palate is not a serious handicap. Her initial application for a judicial review was rejected by a judge last month, but at the high court in London today Lord Justice Rose and Mr Justice Jackson reversed that decision.

Ms Jepson, 27, who as a teenager had corrective surgery on a congenital jaw defect, argues the law should not allow abortions for "trivial reasons".

She welcomed the court's ruling, saying: "Each step in this process has been taken with trepidation. I have been encouraged by the public's support. I hope that we shall succeed at trial and recognise again the value and dignity of our common humanity, disabled or able-bodied, no matter what we look like.

"I am very thankful that the court has decided today to allow my case to go to trial. My teenage years were difficult due to facial abnormality. I also have a brother with Down's syndrome. We both live positive and fulfilling lives.

"The baby in this case did not have this opportunity, despite the availability of excellent and routine medical help. The benefits of this surgery would have been positive for both the child and family.

"However, the advice of the Royal College and the conduct of the doctors involved denied the baby these opportunities. The inaction of the police sadly betrays the true value of this baby's life.

"Finally, the positive response of the public as I have embarked on this litigation has been surprising and overwhelming. Each step has been taken with trepidation. I have been encouraged by the public's support.

"I hope we shall succeed at trial and recognise once again the value and dignity of our common humanity, disabled or able-bodied, no matter what we look like."

There was no immediate comment from West Mercia constabulary.