LONDON (AP) — New British opposition leader Ed Miliband triumphed against his better known brother in the race to become Labour Party chief by showcasing his razor sharp intellect and common touch, skills his supporters say will help him oust Prime Minister David Cameron at Britain's next election.

The 40-year old ex-energy and climate change secretary is known for his grasp of complex policy, but also his easy manner with the public and relaxed speeches, which he often makes without reference to any notes.

His victory over elder brother David Miliband, the 45-year-old former Foreign Secretary, was a surprise to those who long regarded the elder lawmaker a favorite to succeed former prime minister and party leader, Gordon Brown.

A protege of Brown, Ed Miliband served as an adviser to the ex-leader during his time as Britain's Treasury chief and was selected to draft the manifesto for the party's failed 2010 election campaign. Before his election to the House of Commons in 2005, Miliband spent a yearlong sabbatical at Harvard, where he taught economics and developed ties to Sen. John Kerry.

He has often used his relative inexperience at Parliament to his advantage, presenting himself as a candidate untainted by decisions taken during Tony Blair's tenure to join the 2003 invasion of Iraq.

"Part of Ed Miliband's appeal to the party has been — in the slogan that they've used — that he talks human. The suggestion being that his older brother is a bit of a wonk, too policy orientated, whereas the younger brother Ed can communicate better to ordinary people," said Lance Price, a former press adviser to Blair and co-author of a forthcoming biography on the Miliband brothers.

Dubbed "Red Ed" by opponents, he has drawn criticism for setting out policies which would return the Labour party toward its traditional left-wing roots, breaking from Blair's centrist philosophy. Miliband has advocated hefty taxes for high earners, permanent curbs on bankers' bonuses and a tougher bank levy.

Miliband followed his brother into Britain's Cabinet in 2007, and was praised after introducing legislation committing the U.K. to make 80 percent cuts to carbon dioxide emissions by 2050.

The young legislator used his climate change brief to carve out an international reputation, leading Britain's delegation at the Copenhagen climate conference in December. Miliband won plaudits after he dashed from his hotel bedroom to scupper a 4 a.m. attempt by Sudan to veto an agreement at the summit.

Like his elder brother, Ed Miliband was raised by Polish-Jewish parents rooted in academia and politics. Their late father, Ralph, was a famed Marxist scholar who fled to Britain from Belgium during World War II, and mother, Marion Kozak, is an acclaimed leftist intellectual.

During the campaign, the younger candidate quipped that both he and brother David were too moderate for their mother's political views

Miliband lives in north London with partner Justine Thornton — a high flying lawyer — and their son Daniel. Thornton is pregnant with the couple's second child.