UK consumers increasingly turned to plastic in the spring and early summer, with figures showing a rise in the use of credit, debit and charge cards.The number of transactions grew by 12% in the year to the end of June, the highest annual rate since 2008, according to UK Finance.The value of spending also rose, accelerating to 7.2%.Lenders face an upcoming deadline to prove to regulators that they are not lending recklessly.The Bank of England has consistently expressed the need for vigilance over growth in the consumer credit market during “benign” economic conditions, at a time when household income has been relatively stagnant.Extending debtThe latest round-up of statistics show that 77 million more purchases were made on cards in the second quarter of the year than in the first three months of 2017.An extra £110m was spent on cards in the second quarter, compared with the first quarter. Some of that can be explained by the rising cost of living, with the inflation rate having risen over the same period.On an annual basis, growth in the total value of debit card purchases in the year to the end of June was 7.2%, Low-value contactless payments have reduced the amount spent on each typical transaction, but card use has become much more frequent.The total value of credit and charge card purchases was up 6.9% annually by the end of June. There is continuing concern from debt charities about the levels of personal debt and whether this is creating repayment issues ahead.In April, May and June, annual growth in net lending on credit cards – taking spending and repayments into account – was at or above 9%, the UK Finance figures show.The Bank of England’s Prudential Regulation Authority (PRA) highlighted various concerns during a review of lending in personal loans, credit cards and car finance. It told lenders to prove by September that they had been acting responsibly.One issue it raised was the length of 0% credit card balance transfer offers, which have increased sharply in the last five years. The length of these interest-free deals can extend to 43 months, or three-and-a-half years, with the average at nearly 30 months.