An investigation into claims that some doctors are granting women illegal abortions based on the sex of their unborn baby has been launched by the Department of Health.

It has been sparked by an undercover newspaper investigation into sex-selection abortions, secretly filming doctors at British clinics agreeing to terminate foetuses because they were either male or female.

The doctors were also allegedly recorded admitting they were prepared to falsify paperwork to arrange the illegal abortions.

Health Secretary Andrew Lansley said he was "extremely concerned" about the allegations made by the Daily Telegraph, and has instructed officials investigate.

He said: "I'm extremely concerned to hear about these allegations. Sex selection is illegal and is morally wrong.

"I've asked my officials to investigate this as a matter of urgency."

The newspaper said undercover reporters accompanied pregnant women to nine clinics in different parts of the country and in three cases doctors were recorded offering to arrange terminations after being told the women did not want to go ahead with the pregnancy because of their unborn child's sex.

In the UK, abortions are allowed on certain grounds, including that continuing with the pregnancy would be a greater risk to the woman's life, physical or mental health than ending the pregnancy, continuing would be more of a risk to the physical or mental health of any of the woman's existing children and there is a real risk the child would have a serious physical or mental disability.

In September Tory backbencher Nadine Dorries and Labour's Frank Field lost a Commons vote on the issue of counselling.

They wanted to prevent non-statutory abortion providers such as Marie Stopes and the British Pregnancy Advisory Service (BPAS) from offering counselling.

Dorries said that, because they receive money for carrying out terminations, the organisations have a vested interest.