Former British diplomat Andrew Waller, who was a policy advisor at the Syria Office while Khalil worked there, told MEE that the US government's depiction of Khalil was false and defamatory.
"He went through a vetting process to get the job and was cleared to work on sensitive issues for the British government," Waller said
"It's outright defamation what Trump has done. Mahmoud is an extremely kind and conscientious person and he was loved by his colleagues at the Syria Office," he added.
"You couldn't find anyone who'd say a bad word about him, he was very good at his job."
The Chevening scholarship, which is funded by the Foreign, Commonwealth and Development Office (FCDO), describes its mission as being to "support UK foreign policy priorities and achieve FCDO objectives by creating lasting positive relationships with future leaders, influencers, and decision-makers".
Waller described it as a "flagship UK soft power policy"."It brings the brightest students from around the world to UK universities. Mahmoud ran its Syria programme and interviewed hundreds, if not thousands, of applicants on behalf of the British government."