That is the case argued by Dr Peter Sanders
He made the claim on a Radio 4 Today programme interview/debate, and has substantiated on his blog.
It is a long post and well worth reading, but the summary is this:
So where does this leave doctors? Let me sum it up:
1.There is no evidence that continuing with an unwanted pregnancy poses any greater risk to a pregnant woman’s mental health than an abortion does and yet 98% of abortions are authorised on these grounds
2.The doctors who are authorising these abortions are not therefore doing so ‘in good faith’
3.These abortions are therefore unlawful under the Abortion Act 1967 and Offences Against the Person Act 1861 and those doctors who are carrying them out are committing a criminal offence
4.Those doctors who are authorising them are knowingly and wilfully making false statements on legal documents and are thereby committing an offence under the Perjury Act 1911
5.These offences under the Abortion Act and Perjury Act both carry custodial sentences
His blog is generally worth a look, too. See, for example, his comments on the BBC and Gay issues...
H/t Blondpidge on Twitter.