The highest-ranking uniformed officer in the US military has said he believes the ban on gays serving openly must be lifted.

Admiral Mike Mullen, who is chairman of the Joint Chiefs of Staff, told a Senate Armed Services Committee hearing earlier today (Tuesday) that repealing the 1993 law was “the right thing to do”.

He is the most senior officer yet to call for repeal.

Mullen stressed he was”speaking for myself and myself only”.

But he added that he was “troubled” by a policy which makes people “lie about who they are in order to defend their fellow citizens.”

The law allows gays and lesbians to serve in the military so long as they do not reveal their sexual orientation or engage in homosexual behaviour. They can be fired if outed by a third party.

Mullen said that although there would be some practical difficulties in repealing the law, he felt the military could handle it, even at during the two wars abroad.

Defence secretary Robert Gates told the hearing that his chief legal advisor and a four-star Army general would lead a year-long review into how the ban can be lifted.

The Pentagon’s top legal counsel, Jeh Johnson, and General Carter Ham, who leads Army forces in Europe, will conduct the review.

Last week, President Barack Obama promised he would work to repeal the 1993 law this year. This is unlikely to happen in 2010, as the review is scheduled to last 12 months.

The law was implemented by President Bill Clinton as a compromise on an outright ban on gay troops. It means gays and lesbians can serve as long as they do not engage in homosexual behaviour or reveal their sexual orientation to their superiors.

The law is often known as Don’t Ask, Don’t Tell, as senior officers are barred from asking servicemembers about their sexuality. However, they can be outed by another person.

Since the law came into force, an estimated 13,000 servicemembers have been dismissed.