The boom in consumer borrowing across Britain has cooled to the slowest annual growth rate in four years, according to official figures, as households rein in their spending.

The Bank of England said annual consumer credit growth slowed to 6.6% in December, continuing a trend for weaker levels of household borrowing on credit cards, personal loans and car finance deals.

In a reflection of the slowdown in consumer spending over the key festive shopping period, the amount borrowed last month dipped to £700m, below the average £1bn per month for the previous six months.

The Bank said credit card borrowing was particularly weak, with only £100m put on plastic last month compared with an average of about £300m per month since July.

The latest snapshot is likely to stoke mounting concerns over the state of the British economy with fewer than 60 days to go before Brexit. It also comes after the Bank said borrowing on credit cards was expected to plunge to the lowest level since 2007 over the three months before Brexit.

Howard Archer, chief economic adviser to the EY Item Club, said: “Heightened concerns over the economic outlook amid Brexit uncertainties and the very low household savings ratio are seemingly limiting willingness to borrow.”

Samuel Tombs, the chief UK economist at the Pantheon Macroeconomics consultancy, said the decline in the flow of borrowing was probably a key driver behind the slowdown in growth in households’ spending last year. “The unsecured borrowing boom is over,” he said.

Consumer spending rose by 2.7% in 2018, an annual slowdown in comparison with the peak of 4.7% seen in 2016. Appetite for bigger ticket purchases has also fallen in recent months as Brexit nears, according to the Bank.

Although real wage growth has strengthened in recent months, households came under intense pressure after the Brexit vote when the drop in the value of the pound pushed up the cost of importing goods to Britain. Mark Carney, the Bank’s governor, estimated the Brexit vote cost households about £900 each.

While there are fears over the health of the economy, the easing growth of consumer credit may, however, come as a welcome sign that households are not sliding further into the red.

Threadneedle Street had previously sounded the alarm over the borrowing boom, as household debt surpassed the levels seen before the financial crisis, with warnings to banks to rein in riskier lending.

Economists blamed the explosion of debt on weak wage growth, government benefit cuts, as well as intense competition among credit card providers offering cheap deals and a shift by consumers to buy cars on finance packages.

The annual growth of consumer credit has gradually slowed since a peak of 10.9% in late 2016, although at 6.6% it still remains double the rate of wage growth in Britain.

Outstanding balances for consumer credit total £215.6bn, higher than the peak seen before the financial crisis.

Joanna Elson , chief executive of the Money Advice Trust, the charity that runs the National Debtline support service, said the continued growth and high level of debts remained worrying despite the slowdown.

“For the majority of households able to make repayments this is unlikely to be a concern. However, we know that there are many people walking a financial tightrope where one change in circumstances can be all it takes to push them into difficulty,” she said.

Personal insolvencies jumped in the final three months of 2018, sending the total number of people going bust last year in England and Wales to the highest level since 2011.

Debt advisers blamed Brexit uncertainty, sluggish growth in workers’ pay and tighter credit rules forcing more people to declare themselves insolvent.