An estimated 4.5 million credit card holders in the UK are lured into increasing debt by companies increasing their credit allowances.

A study from price comparison company uSwitch showed almost a quarter of UK credit card holders end up spending more on credit after their limits are increased without prior consent.

More than half of the 31.3 million card owners in the UK have had their credit limits increased by credit companies without first giving their permission for them to do so. uSwitch polled 2,003 adults in the UK with a credit card account in early 2016.

"With household debt on the rise, providers shouldn't encourage customers to bite off more credit than they can chew," said Tashema Jackson, a money expert at uSwitch. "Consent, and ultimately control over their finances, need to be in the hands of consumers. Too many are in the dark about how they need to opt out of increases, or fail to do so because of the effort it will take them to contact their provider."

The average amount with which the limit is increased is £1,300 (€1,710, $1,860). uSwitch found that 12% of surveyed credit card holders had their limits increased by £2,500 or more.

The price comparison and switching company is urging the Financial Conduct Authority (FCA) to prohibit credit card companies from increasing limits without the account holders' permission. The FCA launched a credit card probe in November 2014 after concerns about rising debts from credit cards.

The watchdog discussed its interim findings in November 2015, saying competition in the market is "working fairly well", but the FCA issued a consumer warning, saying it is worried about the number of card holders increasing their spending.

An FCA spokeswoman told IBTimes UK one of its key recommended remedies is to give consumers more control over their credit card limits.