Veteran Labour MP Geoffrey Robinson has denounced claims that he was a spy for communist Czechoslovakia during the Cold War as a “complete fabrication”.

The Mail on Sunday reported that, according to documents from the Czech archives, Mr Robinson passed information to the StB state security service for three years during the 1960s.

The material was said to have included highly sensitive details relating to Britain’s Polaris nuclear deterrent as well as Nato briefing notes.

But in a strongly worded statement, a spokesman for the MP – who served as a minister under Tony Blair – said the allegations were “a lie”.

“These allegations are highly defamatory and false and Mr Robinson strongly refutes them,” the spokesman said.

“The allegations, which are apparently based on documents put together by Czech authorities in the 1960s, are a complete fabrication.

“At no time did Mr Robinson ever pass confidential government documents or information to any foreign agent and he did not have access to such material.”

At the time of the alleged contacts, Mr Robinson – now aged 80 – was said to have been working in the research department at Labour Party headquarters at Transport House.

He subsequently went on to work for the newly-formed Industrial Reorganisation Corporation (IRC), Prime Minister Harold Wilson’s attempt to restructure British industry.

According to the Mail, between 1966 and 1969 he held 51 meetings with a Czech handler, during the course of which he was said to have passed on 87 pieces of intelligence.

He was said to have been given the codename Karko and the material he handed over was said to include information relating to plans to upgrade Polaris and the withdrawal of British troops from West Germany.

Mr Robinson was said to have attracted the interest of the StB, in part because of the access they believed he had to Foreign Secretary George Brown and Defence Secretary Denis Healey.

The spokesman for the MP said that the translation of the only document which he had been shown – a “partial” document dated February 19 1974 – did not support the claims.

“It describes him as ‘concurrently a Secretary to the Minister of Defence.. Mr Healey’. He was never a secretary to Mr Healey,” the spokesman said.

“At the end of the document, it states ‘these moments were neither proven nor clarified’ so even on its face this document is not proof that such activity took place.”