SHOPWORKERS’ union Usdaw distanced itself from executive member John Barstow yesterday after he warned that Jeremy Corbyn was “an issue of concern for national security.”

Sussex-based Mr Barstow said the Labour leadership frontrunner should be opposed for being “equivocal on IRA terrorism” and a threat to “market confidence.”

“To Usdaw, support for the integrity of our United Kingdom and support for HM Forces are non-negotiable qualifications for holding office under Her Majesty,” he wrote in a letter to the Financial Times.

“Many shop assistants fell victim to IRA terrorism in Belfast, Manchester and London. Also many Usdaw members have worn the Queen’s uniform and have had family members who have.”

Mr Barstow is vice-chair of Conservatives at Work, a “recognised organisation within the Conservative Party” for members “interested in industrial and workplace matters.”

An Usdaw spokesman said: “He’s certainly speaking in a personal capacity.”

Usdaw is backing Andy Burnham.