David Miliband's local Labour party has said they want to choose their own MP, something he said they have not done in living memory.
John Anglin, secretary for the Constituency Labour Party in South Shields, said: "We are very surprised and it's a great loss to the Labour Party but that is what he has decided to do.
"He's done a lot of good work up here, with schools especially, but he's got a family and he knows what he wants to do.
"We wish him all the best but now we have to concentrate on South Shields and make sure we get a good MP.
"We want to make sure we are allowed to choose our own MP, something we have not done in living memory.
"We have a Labour-run council, which is doing great work, and we have the people up here who are capable of becoming an MP."
David Miliband was nearly Prime Minister, and nearly Labour party leader, but his brother's rise has led him to take a back seat.
David Miliband will resign as an MP to take up a job in America, a move which is set to be announced today.