Diplomats will no longer be able to conceal their “vile conduct” with immunity, legal experts claim, after a Qatari attaché who allegedly called his driver a “black slave” scrapped his defence.

Abudullah Ali Al-Ansari yesterday told his legal team to “withdraw from the proceedings immediately” - just one day after giving evidence at Central London Employment Tribunal. In what could potentially spark a diplomatic row, the Qatari Embassy claimed that proceedings were “incompatible with the dignity and privileges of its diplomatic personnel”.

On Monday The Telegraph reported how Mr Al-Ansari had allegedly subjected Mahamoud Ahmed, his 79-year-old former driver of Somali heritage and the Qatari Embassy’s night security officer, to mental and physical abuse over a number of years. He allegedly called him “dog”, “donkey” and a “black slave” while working at the country’s Mayfair premises.

The court heard that he was treated like his “personal slave” who was “on call 24 hours a day, 7 days a week” until he was sacked in 2013 and was twice physically assaulted by Mr Ali Al-Ansari. He was also allegedly offered a £50,000 bribe by him to drop the unfair dismissal case against him in a bid to “buy his silence”.