British scientists have developed a hormone-free contraceptive pill for men they say would make them infertile for some hours.

The tablet, developed by researched at King's College London, can be taken hours before sex and would prevent a man from being able to impregnate a woman. However, his fertility would return to normal within a few hours, reported the online edition of Daily Mail.

Contraceptive pills available in the market now are only for the exclusive use of women. Annual worldwide sales of these female pills are worth 21 billion pounds.

Currently men who want to take responsibility for contraception have limited choice with their options extending to condoms, vasectomy or simple abstinence.

The new pill developed by Nnaemeka Amobi and other researchers would be more likely to be trusted by women because they are not relying on their man having to remember to take his pill every day for it to work.

Experts believe it could transform family planning by allowing couples to share the responsibility for contraception - a role that traditionally falls on women.

John Guillebaud, one of Britain's leading experts on contraception, described the pill as "a brilliant discovery".

He said its strength lay in its ability to prevent pregnancy without using hormones, which could cause side effects such as hot flushes and moodiness.

Other male pills are under development but many of them are based on hormones that trick the brain into switching off sperm production. These are typically being developed as injections, implants and patches .