Updated

LONDON (AP) — A former Cabinet minister considered one of ex-Prime Minister Gordon Brown's closest colleagues is joining the race to lead Britain's Labour Party.

Lawmaker Ed Balls will run against brothers David and Ed Miliband — also former ministers in Brown's cabinet — in the race. They announced their intentions last week.

The Oxford- and Harvard-educated 43-year-old announced his candidacy on Wednesday.

John McDonnell, a leftist member of the party, has said he'll try to muster the support required to run, but it's considered unlikely he'll succeed.

The leadership will be decided in September at Labour's annual conference. Labour's interim leader Harriet Harman said she won't run to replace Brown.