Alan Milburn, the former Labour cabinet minister who chairs the UK government’s social mobility commission, announced that he and all three of his fellow commissioners were resigning. He said the government is too preoccupied with Brexit to build a fairer society.

As reported by The Associated Press (AP), the resignations are a blow to Prime Minister Theresa May, who has promised to tackle social injustice.

Since May took office in mid-2016, much of the government’s time and energy has been consumed by divorce negotiations with the European Union.

In his resignation letter published on December 3, Milburn said the government “does not have the necessary bandwidth to ensure the rhetoric of healing social division is matched with the reality.”

The government said Milburn’s term in office has ended and he was due to be replaced.