difficult

“It’s going to be very difficult to pay off.”

In the letter to his 17-year-old son, who he has not publicly named, Sir Keir said there were "pressures on young men that are difficult to talk about".

He added: “And I felt that I had addressed what was a difficult situation internally as early as I could.”

Thomas also pointed out that smaller companies have seen their return on capital shrink, making it more difficult for them to create value for shareholders.

“This is good evidence that while earnings estimates are always subject to negative revisions, it is difficult to argue that we are in a valuation bubble currently,” he said.