A leading Republican has said that the party needs to change if it wants to have a future in America.

Colin Powell also said it was time for the US to re-evaluate the ban on openly gay, lesbian and bisexual people serving in the country’s Armed Forces.

The former Chairman of the Joint Chiefs of Staff served under President Bush as US Secretary of State from 2001 to 2005, but he backed Democrat Barack Obama for President.

In an interview on CNN Mr Powell said he still thinks of himself as a Republican, but he had a stark message for the party just weeks after it lost the White House and seats in the Senate and House.

“I think the party has to take a hard look at itself,” he said.

“There is nothing wrong with being conservative.

“There is nothing wrong with having socially conservative views — I don’t object to that. But if the party wants to have a future in this country, it has to face some realities.

“In another 20 years, the majority in this country will be the minority.”

President-elect Obama opposes the ban on gays in the military, known as Don’t Ask, Don’t Tell.

While Mr Powell has spoken out on the subject before, his experience as a military and political leader carries considerable influence in Washington DC and will boost those calling for an early decision on DADT.

Congressman Barney Frank, who is gay, has said he thinks there will not be an attempt to overturn the ban until after US troops have pulled out of Iraq while others have speculated that DADT may not be tackled until 2010 at the earliest.

“We definitely should reevaluate it,” Mr Powell told CNN.

“It’s been 15 years since we put in DADT which was a policy that became a law.

“I didn’t want it to become a law but it became a law. Congress felt that strongly about it.

“But it’s been 15 years and attitudes have changed and so I think it is time for the Congress, since it is their law, to have a full review of it, and I’m quite sure that’s what President-elect Obama will want to do.”

A Washington Post/ABC News poll published in July found that three-quarters of Americans think that openly gay, lesbian and bisexual people should be allowed to serve in the military.

Support for gays in the military has steadily increased, from 44% in 1993 to 62% in 2001 to 75% today.

It was Republican opposition that forced then-President Bill Clinton to abandon his pledge to allow gay people to serve and signed DADT into law.

Since 1993 gay people who do not reveal their sexuality can serve, and commanding officers are not meant to ask service personnel about their sexual orientation.

More than 12,500 gay men and women have been discharged under the current law, at an estimated cost of more than $363 million (£182.6m).

The current policy prohibits anyone who “demonstrates a propensity or intent to engage in homosexual acts” to serve in the US Armed Forces.

In May the Chairman of the US Joint Chiefs of Staff said that Congress, and not the military, is responsible for the ban on openly lesbian, gay and bisexual Americans from military service.

Speaking to graduating cadets at West Point military academy, Admiral Mike Mullen said that DADT is a law that the Armed Forces follow.

“Should the law change, the military will carry that out too,” he said.

President-elect Barack Obama backs repeal.

In an interview with Gay History Project in September, he said he would not use the office of President to abolish it.

“I want to make sure that when we revert Don’t Ask, Don’t Tell, it’s gone through a process and we’ve built a consensus or at least a clarity of that, of what my expectations are, so that it works,” he said.

“My first obligation as the President is to make sure that I keep the American people safe and that our military is functioning effectively.

“Although I have consistently said I would repeal Don’t Ask, Don’t Tell, I believe that the way to do it is make sure that we are working through a process, getting the Joint Chiefs of Staff clear in terms of what our priorities are going to be.

“That’s how we were able to integrate the Armed Services to get women more actively involved.

“At some point, [you’ve] got to make a decision that that’s the right thing to do, but you always want to make sure that you are doing it in a way that maintains our core mission in our military.”