A North Korean nuclear negotiator who was reported to have been executed over the failure of the February Hanoi summit between Kim Jong-un and US President Donald Trump is still alive, South Korean intelligence said on Tuesday.

News of Kim Hyok Chol’s death by firing squad as part of a purge of top North Korean officials was first reported in South Korea’s Chosun Ilbo newspaper in late May and generated headlines around the world.

However, the National Intelligence Service contradicted that account on Tuesday, telling a closed-door meeting of parliamentarians in Seoul that reports of his demise were greatly exaggerated.

The meeting between Kim Jong-un and Mr Trump in Vietnam earlier this year had been billed as a landmark summit to make progress on nuclear disarmament, but it ended abruptly without a deal after a disagreement over sanctions.

The official in question - Mr Kim, a former ambassador to Spain - and four others who were responsible for laying the groundwork for the summit were alleged to have been charged with espionage on behalf of the US and executed at Mirim airport, near the capital, Pyongyang.

The same report claimed that Kim Yong Chol, a former spy chief, who travelled to Washington in the run-up to the summit, had been banished to a labour camp. It said that Kim Yo-jong, the leader’s sister, had also fallen out of favour and been told to keep a low profile.