Rules restricting the advertising of condoms on TV could also be relaxed under proposals put forward in an effort to halt high rates of teenage pregnancy.

Adverts for pregnancy advisory services could be allowed in prime-time evening slots on the major channels and radio following consultation by advertising watchdogs.

But advertisers must stipulate if the service does not refer women directly for abortion under the new proposals.

One of Britain's biggest independent pregnancy advisory service, whose clinicians also perform abortions, said it would immediately consider running adverts.

Julie Douglas, head of marketing at Marie Stopes International, said: "I don't know if we could afford to do it in prime-time TV, but it would be a very interesting thing to do."

The new law could come into force after a review of the Advertising Codes carried out by Committee of Advertising Practice (CAP) and the Broadcast Committee on Advertising Practice (BCAP).

The proposals from BCAP said: "Because it considers that women who are or might be pregnant and are considering abortion merit specific protection under the BCAP Code, BCAP proposes to include a rule on advertisements for post-conception pregnancy advice services.

"BCAP considers that rule should fulfil two policy objectives - to allow post-conception pregnancy advice services the freedom to advertise and to ensure that advertisements for those services make clear whether the service refers women for abortion."

The bodies, which set out the rules for advertisers, have proposed a series of changes following an 18-month review looking at 2,500 rules and regulations and more than 400 pieces of legislation.