British Secretary of State for Exiting the European Union David Davis | Dan Kitwood/Getty Images Former David Davis aide announces new pro-EU party James Chapman, who has worked for David Davis and George Osborne, will officially announce the new party at a march in London on September 9.

LONDON — David Davis’ former chief of staff James Chapman has confirmed he intends to lead a new pro-EU British political party.

Chapman, who quit the Department for Exiting the European Union (DExEU) prior to the general election, said the party would aim to reverse Brexit without recourse to a second referendum.

The launch of the party, known as "the Democrats," will be officially announced at a pro-EU event that Chapman is seeking to host in central London on September 9.

Chapman, a former political editor of the Brexit-supporting Daily Mail, has become a vociferous critic of the government and Brexit-supporting ministers, including his former boss, Brexit Secretary Davis, and Foreign Secretary Boris Johnson.

Prior to joining the Brexit department, he worked for the former Chancellor George Osborne, who was a key figure in the Remain campaign.

In a statement issued Tuesday, Chapman said: “I did my best to make Brexit work for a year — and it won't. There is no upside and it is clear that every sector of our economy will suffer for decades to come. Project Fear is Project Fact."

“The first duty of our politicians is to stand up for the interests of their constituents — and that means sound money and job opportunities for all," the statement said. "The MPs that have left Britain careering towards a cliff worse than Black Wednesday have failed in that duty and are guilty of misconduct in public office ... It's time for all of those with consciences to put nation before country and make sure we are Great Britain once again — not the Little Britain of Nigel Farage and Vladimir Putin's wet dreams.”

After leaving the Brexit department, Chapman secured a job as a partner at the PR firm Bell Pottinger.