Johnson's departure came a day after David Davis, the British minister in charge of Brexit negotiations, also stepped down in protest of May's new Brexit strategy that pointed to a more "business-friendly" deal with the EU.
The Foreign Secretary, Boris Johnson, quit on Monday, hours after the resignation late on Sunday night of the minister in charge of Brexit negotiations, David Davis. Davis' deputy, Steve Baker, also resigned on Sunday.
Prime Minister Theresa May has defended her Brexit plans.
British journalist and writer Neil Clark told RT how there is now "incredible uncertainty" over how the United Kingdom will go about Brexit negotiations, given a "split" in the party over the country's future trade relations with the EU.
Johnson reportedly compared the promotion of the plan to "polishing a turd".
Those remarks came during the notoriously boisterous prime minister's "question time" at the House of Commons.
"What the prime minister is proposing is a way in which we can ensure we don't have. friction with our trade with the European Union. and here is a practical way in which we can do that", Gauke said.
Johnson was set to attend a North Atlantic Treaty Organisation summit in Brussels on Wednesday, and U.S. President Donald Trump will fly to London on Thursday for his first official visit to the United Kingdom, where he is set to talk to the British prime minister about a range of foreign policy issues. "The prime minister thanks Boris for his work", the statement said. "His replacement will be announced shortly".
Johnson, who assumed his position as foreign secretary in July of 2016, previously admonished then-GOP presidential nominee Donald Trump for his criticism of North Atlantic Treaty Organisation.
The value of the British pound dropped on global markets after Johnson's announcement, having risen after the announcement Friday that a Cabinet deal on Brexit had been agreed.
Johnson, a polarising figure and a former mayor of London, was a leading spokesperson for the campaign calling for Britain's departure from the European Union in advance of a June 2016 referendum.
I am proud to have served as Foreign Secretary in your government.
There was no immediate statement from Mr Johnson to explain his decision to quit, which was seized upon by opposition politicians as a sign of increasing turmoil within Mrs May's administration.
He says "there is now a new secretary of state and we look forward to moving on". Instead, her party actually lost seats and its clear majority in Parliament.
She added: "I do not agree with your characterisation of the policy we agreed at Cabinet on Friday".
In his letter to the Prime Minister, Davis said: "Whether it is the progressive dilution of what I thought was a firm Chequers agreement In February on right to diverge, or the unnecessary delays of the start of the white paper, or the presentation of a backstop proposal that omitted the strict conditions that I requested and believed that we had agreed, the general direction of policy will leave us in at best a weak negotiating position, and possibly an inescapable one".
If she refuses to change course, she could face a leadership challenge.
Long before the Brexit referendum and its aftermath, the Conservative Party was split on Europe, and May has struggled to unite the warring wings under her leadership.