Judgement matters too, of course. There is a reason why these shares are unloved, so most of Lang’s work goes in looking for and selecting those among the dogs that won’t bite him – in other words in avoiding those likely to go bust. These are the shares that have what he calls deep value, in the sense that though they have their troubles they also have a product people want, and a market position that should allow them to continue to deliver it. So he asks himself a basic but key question: will the company still be in business in five years’ time even if it does not actually improve, and will the reasons it is currently unloved still be with us? That, of course, is a call he does not always get right – Mayflower, a motor-vehicle body manufacturer that once boasted John Major on its board – was one that did not make it. But on balance it works out.

The other point Lang makes is that there are always people looking at bombed-out shares and hoping to buy just as their fortunes begin to improve. He in contrast buys when the company still looks awful because the biggest kick in the price comes before the turn is obvious. Once it is visible it is too late. You have to go in early and not worry if the shares fall further – nor give in to disappointment or frustration when, just as likely, they go nowhere for years.

One of the world’s most famous and successful investors, Sir John Templeton, once said that an investor could never beat the market by doing what everyone else did because everyone else constituted the market. You have to leave the lemmings to do what lemmings will do and only by having the courage to be different could you hope to be a success.

Warren Buffett, arguably today’s most famous and successful investor, takes much the same view. In essence much of what he does also echoes Lang, albeit on a massively larger scale because he buys basic businesses with good brand names when no one else wants them – and then holds on to them. As a consequence he has become the second or third richest man in the world.

And the wonderful thing about this as an investment strategy is that it will never be popular.
By definition, betting against the crowd never is.