Women will now be allowed into Britain's Royal Navy submarine service, Defence Secretary Philip Hammond announced Dec. 8, ending a ban that has been in place since 1993.
Nearly 10 percent of those serving in the Royal Navy are women.
The first group of women officer volunteers will begin training next year and are expected to arrive onboard one of the four Vanguard-class ballistic missile submarines in late 2013, the Royal Navy said in a statement.
Female enlisted ratings will be recruited and trained from 2014.
Women also will be assigned to new Astute-class hunter-killer attack submarines beginning in 2016, the service said, following "necessary modifications" to the boats' accommodations.
"Our primary objective in the Royal Navy is maintaining our operational effectiveness both now and in the future," Vice Adm. Charles Montgomery, the Navy's second sea lord and head of personnel and training, said in the statement.
"This carefully considered decision will allow the Submarine Service to draw on the widest range of talent and skills of our people - those in service and those yet to join."
Hammond, in his first address as the new defense secretary, said the move will help the service maintain operational effectiveness.
"The Royal Navy has always been at the forefront of innovation," Hammond said, "and this decision represents another step in its distinguished tradition of recognizing the contribution of its people and making the very best use of the talent from which it can recruit."
The 110-year old submarine service has never allowed women to serve on its undersea craft. Women began serving at sea with the Royal Navy in 1990, but the service decided in 1993 not to allow them on submarines, citing health concerns. At issue were worries that higher levels of carbon dioxide in a submarine's atmosphere threatened women's health.
The Navy statement noted that "recent research by the Institute of Naval Medicine in Gosport showed that these risks were unfounded and that there were no medical reasons for excluding women from service in submarines.
"That research came as part of an 18-month review conducted by the Royal Navy looking at the legal, operational, health, social, technical and financial issues of allowing women to go to sea with the Silent Service."
The U.S. Navy in 2010 reversed a long-standing policy against allowing women on its submarines, and the first group of women is preparing to report this month aboard their first boats. So far, women are being assigned only to large missile submarines, and there are no current plans to allow females to serve aboard smaller attack subs.
No decision on allowing U.S. enlisted women to serve on submarines has been announced.
The objections to women on subs in the U.S. Navy were based more on cultural grounds. In particular, spouses of men serving in subs were often vocal objectors.
Service aboard submarines can be a more grueling experience than on surface ships. The boats are cramped, and passageways, working and living spaces aboard even large submarines are tight. Nuclear submarines can remain submerged for weeks, even months at a time, and submarine sailors are constantly urged to be polite and considerate of their shipmates.