A new book has claimed that Vice President Joe Biden’s surprise backing of same-sex marriage in 2012 pushed Barack Obama into following suit faster than planned.

According to investigative reporter Jo Becker’s new book, ‘Forcing the Spring’, Biden’s shock backing of same-sex marriage in May 2012 was not pre-approved by the president, and sent the White House into chaos.

Biden said in a ‘Meet the Press’ interview, while Obama was still officially opposed to same-sex marriage: “The President sets the policy. I am absolutely comfortable with the fact that men marrying men, women marrying women and heterosexual men marrying women are entitled to the same exact rights.”

Just three days later President Obama, who had previously said his views on marriage were ‘evolving’, followed in Biden’s footsteps, and declared in a sit-down interview that he too supported equal marriage.

According to Becker’s book, Biden’s announcement forced Obama’s hand, and “chaos erupted inside the West Wing after an emailed transcript of the interview landed in the inbox of the White House press team”.

Communications director Shailagh Murray warned Biden on the journey back from the studio: “I think you may have just gotten in front of the president on gay marriage”.

Becker says that senior advisor Valerie Jarrett was furious with Biden, and accused him of “downright disloyalty”.

Biden has since defended himself from claims he deliberately broke ranks to push the president into a position, saying: “I didn’t go out volunteering a position, but when asked a question, I had to respond to it.”

The book also revealed that Obama had sought advice from Ken Mehlman, the gay former chairman of the Republican National Committee, on how best to announce his support.