The Bernie Sanders campaign has hit out at the largest LGBT lobbying group in the US – after they endorsed Hillary Clinton for President.

It was announced today that the Human Rights Campaign had opted to endorse Hillary Clinton for President above the Vermont Senator – who is challenging her for the Democratic nomination.

The HRC’s board of 32 LGBT rights leaders voted unanimously in favour of Hillary Clinton despite her only backing same-sex marriage in 2013 – noting her ground-breaking raft of LGBT policy pledges, committing to a number of revolutionary changes.

Clinton’s plan includes 24 separate pledges across LGBT policy areas, while Sanders lists just seven specific LGBT points.

Despite this, the campaign of Senator Sanders has hit out at the decision – claiming that HRC is colluding with “the establishment” because Sanders is a lifelong supporter of LGBT rights, and has vocally stood up for equality for a number of years.

His spokesperson Michael Briggs told the Washington Blade: “It’s understandable and consistent with the establishment organizations voting for the establishment candidate, but it’s an endorsement that cannot possibly be based on the facts and the record.”

He added that Senator Sanders deserved the nomination as he has “by far the most exemplary record on gay rights of any candidate ever in American history”.

The spokesperson continued: “Who knows what prompted the Human Rights Campaign to do what it does — I have trouble myself figuring why they do some of the things they do over the years.

“I think the gay men and lesbians all over the country will know who has been their champion for a long, long time and will consider that as they make up their mind on support for his campaign.”

HRC responded: “There are certainly several friends of equality in this race, but the 32 community leaders who comprise HRC’s Board of Directors have unanimously decided that Hillary Clinton is the champion we need to fight for us each day on the campaign trail and every day in the White House.

“She has a strong record, a strong agenda, and a strong ability to win against any Republican running on an anti-LGBT platform in November and lead from Day One.”

In a statement to PinkNews, Hillary Clinton said: “I’m honoured to receive the endorsement of the Human Rights Campaign—the nation’s largest organization working to achieve full equality for lesbian, gay, bisexual, and transgender Americans.

“Thanks to the Human Rights Campaign and millions of advocates across the country, we’ve made tremendous progress. But our work is far from over. Too many LGBT Americans still face discrimination—in employment, in housing, in education, in health care—because of who they are or who they love. And the stakes in this election couldn’t be higher.

“The Republican candidates for president have not only hurled hateful, insulting rhetoric about the LGBT community—they’ve made it clear that if elected, they will roll back the rights that so many have fought for.

She continued: “As President, I will continue to fight alongside the LGBT community to pass the Equality Act. I’ll support efforts to allow transgender personnel to serve openly, and I’ll end the dangerous practice of ‘conversion therapy’ on minors. I’ll expand access to HIV prevention and treatment, and confront the epidemic of violence facing the transgender community, especially transgender women of colour.

“And I’ll continue the efforts I led as Secretary of State to advance the human rights of LGBT people around the world.

“I’m proud to stand with the Human Rights Campaign in this fight. Together, we can and will make our country—and our world—more just, fair, and equal for generations to come.”