The US Secretary of Defence has intervened after a lesbian Congresswoman’s partner was barred from accompanying her on a military aircraft during an official trip.

It is reported that the Speaker of the House of Representatives, Nancy Pelosi, phoned Defence Secretary Robert Gates to ask him to intervene.

Tammy Baldwin, who represents Wisconsin’s second district, is the only openly gay woman in Congress.

The Pentagon had reportedly refused to allow her partner Lauren Azar to accompany her as part of a Congressional delegation using a military plane, citing rules that only allow husbands and wives of politicians to do so.

Mr Gates ordered she be allowed to go after Ms Pelosi spoke to him about the issue.

Ms Baldwin, who has been a member of the House of Representatives since 1999, has declined to comment on the story.

The position of domestic partners of US government officials and politicians is frustrated by the Defence of Marriage Act.

Passed in 1996, it bars the Federal government for recognising any same-sex marriage, even if it was conducted in a US state where such marriages are legal.

In December a former US ambassador left his post at the State Department after criticising Secretary of State Condoleezza Rice’s treatment of gay people.

Michael E Guest left after more than 26 years as a form of protest against regulations that he considered as unfair to same-sex partners of foreign service officers.

The 50-year-old, who is openly gay, served as a US ambassador to Romania when Bush took office.

He was the first out gay person to be confirmed by the Senate to an ambassadorial post.

Since his return home in 2004, he has appealed directly to the US Secretary of State Rice to end gay discrimination.

According to Guest, under the current regulations only a US State Department’s spouse can claim several rights which are denied to unmarried partners and same-sex partners.

These include issues such as the lack of training for same-sex partners to recognise terrorist threats, the lack of medical care and the need to pay for one’s own transportation when one’s partner is on duty.