North Korea leader Kim Jong-un has reportedly had a former key crony, Ri Yong-ho executed in a savage clampdown inside his regime, sources have claimed.

Ri Yong-ho, who negotiated North Korea’s nuclear deals with the United States, was allegedly executed amid Kim Jong-un’s ramping up of war drills.

The top diplomat, who was formerly the North Korean ambassador to Britain and spoke fluent English, was reportedly executed after being “purged” from Kim’s administration.

Japanese newspaper Yomiuri Shimbun, citing unnamed sources, reported that the 66-year-old had been executed last year.

He was reportedly executed alongside four or five other officials.

All of those executed are believed to have had links to the North Korean embassy in Britain.

South Korean MP Youn Kun-young told the country’s parliament that his county’s National Intelligence Service had confirmed that Ri had been “purged”, but added that “whether he was executed remains unclear”.

Ri is the highest-profile North Korean figure to have been killed for several years.

It comes as Kim – who has been his country’s supreme leader since 2011 – prepares to celebrate his 39th birthday on Sunday.

Ri served as ambassador at North Korea’s shabby embassy in Ealing, west London, between 2003 and 2007.