Same-sex weddings are legal in Canada, where Ms Wyatt is to wed

Senior aircraftswoman Sam Wyatt, 26, met massage therapist Christa McKay, 25, during an 18-month RAF posting in Canada.

Ms Wyatt, who recently served in Iraq, is marrying Ms McKay at the end of the month in Toronto, in Canada, where same-sex weddings are legal.

But Ministry of Defence (MoD) officials have turned down the couple's request for shared housing at RAF Brize Norton in Oxfordshire, despite the fact that suitable accommodation is available.

'Totally unfair'

Ms Wyatt, from Cornwall, who joined the RAF six years ago, has threatened to leave the force three years early unless the MoD backs down.

She said: "I think the MoD are being totally unfair.

"Gays are allowed to be in the military now - why can't they recognise same-sex marriages?"

An MoD spokesman told BBC News Online: "The situation is that gay marriages are not recognised within the UK, therefore those individuals are not eligible for married quarters.

"The MoD is looking at this for the future but at the moment that is the situation."

A ban on homosexuals in the armed forces was lifted in January 2000.