Aneurin “Nye” Bevan, the Welsh Labour firebrand who spearheaded the creation of the NHS, was monitored by security services for more than two decades, though his personal file was “remarkably tame”, according to official files released to the public.

Bevan came to MI5’s attention in the 1930s over concerns about his links with known communists, papers released to the National Archives show. Monitoring continued even after he became a minister in the postwar Labour government that created the NHS.

At one point, his links to a known Russian spy led to the then director general of MI5 approaching prime minister Clement Attlee to warn him.

However, the papers show, some in the security services questioned why Bevan was of interest.…