LONDON — It took more than a century, but Britain’s Co-operative Party now has one of its own in No. 10 Downing Street.

Andy Burnham is the first Labour and Co-operative MP to become prime minister — a milestone the longstanding, worker-focused movement’s supporters hope will lead to a radical overhaul of the way Britain works.

The new prime minister is among seven Labour and Co-operative Cabinet ministers, including Deputy Leader Lucy Powell, Business Secretary Jonathan Reynolds and Energy Secretary Miatta Fahnbulleh, along with more than a dozen ministers and parliamentary private secretaries from the movement.