According to accounts filed with Companies House, the company’s net assets grew from £338,000 at the end of March 2018 to nearly £417,000 at the end of March 2019.

The company’s investment portfolio includes a 15% shareholding in Stagecoach, which made up nearly £133,500 of the value.

It also received cash proceeds of £121m from the sale of Alexander Dennis Limited, its largest unquoted investment, in May 2019.

Sir Brian said: “The generation of new opportunities was again strong during the year, and we continue to be rigorous in our selection of investments. We continue to diversify our portfolio and retain a healthy appetite for unlisted investments.

“The results for the year were an improvement on the prior year and demonstrate the significant value that has been added to the portfolio by our employees and managers of our investee companies during the course of the year.”