Millions of Britons are set to experience the first interest rate rise of their adult lives on Thursday, and for some of those who loaded up on cheap credit to pay for cars or cards, that could spell trouble.
The Bank of England is widely expected to hike borrowing costs for the first time in a decade, signalling an end to years of low rates that fuelled a rise in ultra-cheap credit and heavy borrowing on loans, cards and, most notably, cars.
Regulators have clamped down on many of the riskier lending activities that thrived before 2008, from 'payday' loans with annual interest of over 5,000% to self-certified mortgages. Others, like motor finance, have risen to take their place.
Bankers and economists warn that those most indebted could begin skipping payments on cars and credit cards, puncturing a consumer debt bubble 10 years in the making.
A 0.25% rate hike would lead to a median increase in monthly outgoings of £20 for consumers who have contacted StepChange in the last year, according to calculations by the debt advice charity.
That would push the budgets of up to 7,000 of the charity's clients into the red, meaning they can no longer cover essential living costs.
"Our view is that this isn't mortgage apocalypse, but there's a narrow group of people whose household finances are on a knife-edge and a rate hike could be the straw that breaks the camel's back," a spokesman for the charity said.
Consumer credit has grown much faster than household incomes in the last few years, the Bank of England said in June.
In September, it hit £204 billion, with car finance the fastest expanding area that now accounts for around 30% of the total.
Last year, 86.4% of all new car purchases utilised some form of credit, up from 46% in 2006, according to data from the Financing and Leasing Association.
Most deals are done not by banks but through car manufacturers' finance arms, with those from Volkswagen, BMW, Ford Motor Co, Toyota Motor Corp and Renault the biggest in the UK by the amounts they are owed by consumers.
These have risen from £13.5 billion in 2008 to over £36 billion in 2016 - a 168% increase, data from the five firms' financial statements show.
Fifteen percent of mortgage loans are worth more than four times the borrower's income, he said, up from less than 5% in 2005.
With credit widely available, a small but significant number of borrowers have become overburdened with multiple debts, said Peter Richardson, analyst at Berenberg.
Fifteen percent of mortgage loans are worth more than four times the borrower's income, he said, up from less than 5% in 2005.
Most consumer credit is offered on fixed interest rates, so would not be directly impacted by a rate increase.
But with around 40% of mortgage lending on variable rates - and borrowers more likely to default on other loans than miss payments on their home - even a slight hike could leave the most overstretched people choosing to skip other debt payments.
A 0.25%t interest rate hike would increase the monthly payments on an average floating rate loan of £140,000 by around £15 a month, according to Nationwide.
"If you look back at the economics of this ... borrowers with that level of indebtedness become very, very sensitive to shocks, you have much more violent reactions," Berenberg's Richardson said.
Bank of England data shows that outstanding lending on credit cards was at an all-time high of £69.4 billion in September and approaching its pre-crisis peak for other credit lines including overdrafts, personal loans and car finance.
Outstanding lending on these credit lines hit £134.8 billion in September, compared with £138.2 billion in August 2007.