Life is tough for high street retailers and likely to get worse in 2018. That’s the clear message following a difficult Christmas for most shopping chains and signals from the banks that they aim to bring a three-year bonanza of cheap consumer credit to an end, or at least severely restrict its further growth.

Supermarkets were among the survivors as shoppers chose to spend a few extra pounds on food to cope with inflation. But that meant cutbacks elsewhere.

Clothing, shoes and furniture joined a list of items shoppers decided they could do without – or, if they needed them, they went online for a cheap deal.

Next was among the retailers to enjoy a degree of expansion after it was rescued by healthy online sales. Marks & Spencer struggled to make any headway after its failure to entice customers to its website.

If the health of the high street depends on anyone, it is the big discounters like Aldi and Lidl in the supermarket wars and B&M, which is the Primark of food shops, selling household brands such as Kellogg’s and Walkers at knock-down prices.

But few high streets can survive with just discount shops to add to a smattering of charity outlets, bookies and pawnbrokers.

Most towns vie with their neighbours to have at least one department store on their high street or, failing that, some national chains.

Not so long ago, when Debenhams seemed like it would be turning up in almost every corner of the country with a new store, this dream appeared to be coming true.

John Lewis was another department store that was talked about as a candidate for aiding urban renewal in the unlikeliest of places.

The rapid expansion of chains such as New Look, TK Maxx and, more recently, jeweller Pandora has helped keep many smaller centres from looking down at heel.

Sadly, Debenhams had a disastrous Christmas, as did House of Fraser, and both have ditched any expansion plans left over from the 2015 boom times. Cutbacks are the order of the day. M&S is already closing stores, mostly in towns that shoppers have long since started driving past.

New Look has seen sales fall, while profits at TK Maxx and Pandora are down. John Lewis is doing well although, like Next, all the improvement is online, not in its stores.

Soon, even more high streets outside the big cities and successful market towns will have a ghostly pallor.

At the root of the problem is the decline in disposable incomes. With inflation at around 3% and wage rises averaging 2.2%, households are struggling to maintain their standard of living. In a post-EU referendum economy, with uncertainty forcing companies to delay investment, average wages don’t look like rising strongly any time soon.

There was more bad news in the latest Bank of England study of consumer lending. A survey of high street banks found they were planning to severely restrict the generosity displayed in recent years that has pushed unsecured lending up by around 10% a year.

Credit-card balances will be cut back and the length of interest-free periods will be reduced. Cheap loans will be limited to only the safest borrowers.

This move is a response to concerns that the major banks had begun to lend recklessly, repeating the mistakes that led to the 2008 banking crash.

There can be no doubt that some harsh words are welcome from the financial regulator decrying bonus-chasing bankers offering loans to every Tom, Jane and Harriet.

However, they are not so welcome if you are a shop owner or worker who depends on consumers maintaining their shopping habits.

MPs have largely ignored the subject of healthy town centres, leaving the problem to local authorities. Maybe if more of them shopped in their constituencies, they might notice the changes going on.

It is possible that after another tough year, and some more shop closures, they might want the government to start thinking about giving the worst-affected towns a fresh start.

Even if bonds fall, it’s hard to see an end to this era of cheap credit

There are some economic laws that reassert themselves, and some that are victims of changing times. The likely path of borrowing costs – that they rise in good times and fall in bad – is one such law that has failed to conform to previous trends.

For 30 years now, interest rates have been falling, making it cheaper and cheaper to borrow money. This trend has continued during booms and busts on global stock markets, to which the debt markets were previously tied. The 2008 crash accelerated the decline in rates, but it was already well under way.

Today, central banks charge commercial lenders an almost zero rate of interest, allowing mortgage lenders to push loan rates down to historic lows. Even the five increases in the US Federal Reserve’s base rates since 2015 have done nothing to alter the downward trend. US lenders, keen to win business, have squeezed their margins rather than pass on the higher cost of borrowing from the Fed.

But there are several debt-market gurus who think the latest signals from the European Central Bank and the central banks of Japan and China could mark an end to this era of cheap credit.

The price of buying bonds, which is the market’s way of packaging up the debt issued by governments and companies – state and corporate borrowing, in other words – is falling. The interest rate – referred to as the “yield” – on bonds rises as the price falls, and last week the yield on a 10-year US government bond jumped to nearly 2.6%, its highest level for almost a year.

If, as is being signalled, the central banks of China, Japan and the eurozone start cutting back on their purchases of bonds, then, the argument runs, overall demand will fall and so will the price: and such borrowing will become more expensive.

But even if central banks end their role as major bond purchasers, there is still plenty of demand. The world’s financial system is awash with money looking for a home. Bonds remain a popular choice – cushioning any potential fall in price and rise in yield.

Big brains of business enjoy curling up with a good book

On both sides of the Atlantic, book clubs have strong associations with entertainment stars: Oprah Winfrey in the US, for example, and Richard and Judy in the UK. But now there is a new genre of literary cheerleader: the corporate bibliophile.

Mark Zuckerberg and Bill Gates both publish reading lists and encourage readers to follow suit. Among the titles recommended by both tycoons are Yuval Noah Harari’s Sapiens and The Better Angels of Our Nature by Steven Pinker. The Gates and Zuckerberg lists have won approval from cultural peers, including the managing director of Waterstones, but there has been justified criticism of the apparent gender imbalance in their reading. Books by men appear to outweigh those by women.

Hopefully, the Facebook and Microsoft founders will adjust their bedtime reading piles accordingly. That aside, it is surely a good thing that two of the world’s most powerful corporate figures are advocating the attainment of written wisdom. Their peers should take note. Literally.