LONDON (Reuters) – The head of Britain’s Social Mobility Commission has quit, accusing Prime Minister Theresa May of being too fixated on Brexit to improve the prospects of those from less privileged backgrounds, The Sunday Times newspaper reported.

May has vowed to create an economy which works for all Britons but Chairman Alan Milburn, a former minister in Tony Blair’s Labour government, said she was failing to deliver on her promises.

“The worst position in politics is to set out a proposition that you’re going to heal social divisions and then do nothing about it,” Milburn was quoted as saying by The Sunday Times newspaper.

“Talking the talk is all very well, but you also need to walk the walk. I see precisely no chance of making progress. They are so concerned with Brexit that there is no bandwidth to focus on any of this stuff.”

The entire board, including Milburn, has resigned, The Sunday Times reported.

A spokeswoman at the Social Mobility Commission, a public body which monitors progress towards improving social mobility, could not immediately be reached for comment late on Saturday.

Two ministers have quit May’s cabinet in the last month, placing strain on the government as it nears a crucial summit on Britain’s exit from the European Union.

An opinion poll published for the Mail On Sunday newspaper put Labour on 45 percent with the ruling Conservatives on 37 percent, the biggest lead for opposition leader Jeremy Corbyn’s party in a survey by pollster Survation since late 2013.

“An 8 point lead would put the Labour party into overall majority territory if such vote share totals were reflected at the ballot box,” Survation said.