Defeated Labour leadership candidate David Miliband has quit frontline politics, announcing that he will not stand for election to his brother Ed's shadow cabinet.

In a letter to the chairman of his constituency Labour Party, Mr Miliband said he would remain as MP for South Shields.

But he said Labour would be more likely to be able to make ‘a fresh start’ under its new leader if he moved on to the backbenches.

‘I genuinely believe that I can best serve Ed, the party and the country from a new position,’ he wrote.

In his letter to Alan Donnelly, Mr Miliband said his continued presence as a member of the shadow cabinet would be a 'distraction' from his brother's leadership of the party.

And he said he wanted to ‘recharge my political and intellectual batteries’ after 16 years in positions in and around the top of politics and to have more time to spend with sons Isaac and Jacob and partner Louise.

His dramatic announcement comes as nominations close for the election of 19 members of the new Labour shadow cabinet, and just four days after David lost out on the party's leadership by a narrow 1.3% margin to his younger brother.