Sir Laurie Bristow, the UK ambassador to Afghanistan, is taking a short break after intensive efforts to extricate British citizens and Afghans from Kabul.
Martin Longden, a senior Foreign Office official and former envoy to Lebanon, is temporarily in charge. The announcement came as Foreign Secretary Dominic Raab travelled to Qatar for talks on the situation in Afghanistan.
Mr Raab said the UK would not recognise the Taliban "any time soon" but that "engagement and dialogue" with the group was needed.
The focus on the ground is the temporary relocation of the British embassy from Afghanistan to Doha, after the Taliban takeover of Kabul and the rest of the country.
Mr Raab is working with Sir Simon Gass, UK Prime Minister Boris Johnson’s envoy for the Afghan transition, who in recent weeks met senior Taliban officials.
“In talks with the Taliban, Sir Simon has emphasised the importance of them allowing safe passage for those seeking to leave Afghanistan; of standing by their commitments to address the threat from terrorism; and of the importance of an inclusive government that respects human rights, particularly those of women and girls,” the Foreign Office said.
Mr Raab said the future "is going to be a challenge" that would require "a new set of strategies".
He highlighted four priorities: ensuring Afghanistan does not again become a safe haven for terrorists; preventing a humanitarian crisis; maintaining regional stability; and holding the Taliban to its commitment to a more inclusive government.
"Obviously, we'll be looking very carefully at what happens in the field of human rights and the treatment of women and girls," he said.
UK officials dealing with Afghans fleeing the country are regrouping in a new city. A statement said the embassy had “been temporarily relocated to Qatar until it can be re-established in Afghanistan”.
“Dr Longden’s immediate priorities are to meet international partners in Qatar and build up the embassy team,” the Foreign Office said.
In Qatar, Mr Raab will also seek to assess the prospects of Kabul airport reopening and operating, and hold talks with senior Qatar officials.
The Foreign Office said Britain was keen to work with international partners to ensure the Taliban “bear down” on terrorist groups such as ISIS and Al Qaeda.
Britain's last military flight left Kabul on Saturday after moving more than 15,000 people from the city in the two weeks since the Taliban took control of Afghanistan.
Mr Raab was heavily criticised for being on holiday in Crete when the Taliban closed in on the Afghan capital.