US defence secretary Robert Gates has suggested that repealing the ban on gays and lesbians serving openly in the military could take years – and implied it might not happen at all.

Speaking at the Army War College yesterday, he urged a cautious approach over the issue, saying: ““If we do it, it’s important that we do it right, and very carefully.’’

When asked by an officer about the policy, he said it was a “complex and difficult problem”.

Gates also cited the example of racial integration in the 1940s, saying that it took five years for be completed.

He said that gauging opinion on the issue was a particular problem: “To get people’s real feelings about it, you have to have almost a one-on-one private conversation.

“I think it’s very difficult for people to speak in front of their peers about this issue.’’

Gates reiterated President Barack Obama’s support for changing the law, saying: “The president has made it clear where he wants to go.”

The ‘Don’t Ask, Don’t Tell’ policy was introduced in 1994 and allows gay men and women to serve in the military as long as they keep their sexual orientation secret and do not engage in any homosexual acts.

President Clinton found himself embroiled in a fight with Congress over gays in the military soon after he moved into the White House in 1993.

As a Presidential candidate he had promised to allow gays to serve, but when he took office he was forced to accept the present policy in the face of military and Congressional opposition.

Many military officials, including General John Shalikashvili, chairman of the Joint Chiefs of Staff under President Clinton, now believe that gays should be allowed to serve openly.

The current chairman, Admiral Mike Mullen, said an interview after his December meeting with Barack Obama in Chicago:

“He’s been pretty clear that he wants to address this issue.

“I am certainly mindful that at some point in time it could come.”

According to the Servicemembers Legal Defence Network, nearly 12,500 servicemen and women have been discharged under it since its implementation.

It is estimated that up to 45,000 Americans have been discouraged from joining or remaining in the armed forces.