British Foreign Secretary Boris Johnson resigns: Downing St

British Foreign Secretary Boris Johnson has resigned, Downing Street said in a statement today, hours after Brexit Minister David Davis stepped down.

Read more: Brexit minister quits in blow to Britain's May

"This afternoon, the Prime Minister accepted the resignation of Boris Johnson as Foreign Secretary," PM Theresa May's Downing Street office said in the statement.

"His replacement will be announced shortly. The prime minister thanks Boris for his work," the statement said. 

In private, Johnson had reportedly criticised May's plan for retaining strong economic ties to the EU even after Brexit, referring to the plan as "polishing a turd".

Since cabinet approval for the plan on Friday, however, he had refrained from public comment.

He was due to co-host a summit on the Western Balkans in London today but did not show up.

Germany's junior foreign minister Michael Roth tweeted: "We're still waiting for our host".