Stagecoach’s East Coast debacle won’t be helping the investment portfolio of its multimillionaire founder Sir Brian Souter.

Roughly half of Souter Investments’ assets are made up of Stagecoach shares and the fiasco on the East Coast mainline is unlikely to be helping reverse recent earnings dips.

Sir Brian’s investment company suffered pre-tax losses of £84m in its 2016 financial year and £34m in 2017 and Stagecoach’s share price fall of more than a third in the past year could weigh the vehicle down again.

But critics of Stagecoach, whose 90pc-owned joint venture Virgin Trains East Coast will end its control of the East Coast mainline just three years into its eight-year contract, are unlikely to be sympathetic.

Souter Investments still boasted net assets of £366m at the end of March last year but the big question now is whether such heavy exposure to the company he, his sister Ann and brother-in-law Robin Gloag founded in 1980 with his father’s redundancy money will be a help or hindrance.