The Daily Mirror reported late Thursday that Grant Bailey, a 50-year-old security expert for an NGO, had been arrested by Taliban police in Kabul.
Upon inquiry, the Foreign Office stated, "We are aware of the detention of a British national in Afghanistan and we are supporting his family."
Taliban officials did not respond to AFP's request for comment.
According to a security source, Bailey was arrested at gunpoint on Saturday. It added he was thought imprisoned in Kabul.
The source said Bailey had returned to work in Afghanistan weeks after the evacuation of Western military and diplomats in August.
The UK evacuated its troops and diplomats in late August, following the Taliban's takeover of the country when the US withdrew its forces.
Bailey is a project risk manager with substantial expertise in Africa, Central Asia, and the Middle East on LinkedIn.