A debt advice charity saw the number of cries for help from people drowning in payday loan debt almost double last year, including nearly 14,000 clients who were struggling with five or more loans.

StepChange, which said loans are causing "widespread harm and misery", dealt with £110 million worth of problem payday loan debt in 2013.

This cash total related to 66,557 clients, marking an 82% year-on-year increase in the number of people seeking the charity's help with payday debt.

The charity heard from 13,800 people last year who had taken out at least five payday loans and said what it is seeing is "compelling evidence" that the sector must undergo significant reforms.

On average, those people it helps with payday debt have three loans and owe £1,647 - more than their typical monthly income of £1,381.

Two-thirds (62%) of the people it sees with payday loans also owe money on their overdrafts, three-fifths (60%) also have credit card debt and two-fifths (39%) owe cash to catalogue companies.

The Financial Conduct Authority (FCA) will start to oversee payday lenders from April when it takes over regulation of consumer credit.

Payday lenders have faced intense criticism over the last year after evidence has emerged that some appear to have been basing their business models around people who cannot afford to pay their loans back in time, meaning the original cost of the debt balloons and the borrower ends up rolling the loan over and sinking into deeper trouble.

The whole industry is under investigation by the Competition Commission, which will report back later this year.

StepChange said it has seen many cases involving debts which are "excessively" inflated by lenders slapping on extra charges and interest. These include a man who was helped by the charity because his original £200 debt was ramped up to £1,851 in just three months.

The charity wants the FCA to force all lenders to share "real time" information to ensure they have the most up-to-date information about anything that might ring alarm bells when they are deciding whether a borrower can afford a loan.

It also believes lenders should only be allowed to roll over a loan once, as this is a "clear sign" that the borrower is having problems.

StepChange said that if a lender makes an unsuccessful attempt to collect money owed by using a type of recurring payment called a continuous payment authority (CPA) they should take this as a warning that the borrower is in trouble financially.

It believes the lender should not try to dip into the borrower's bank account again until they are satisfied this will not put their customer in danger of financial hardship.

Mike O'Connor, chief executive of StepChange Debt Charity, said: "The widespread harm and misery caused by payday loans continues unabated.

"The industry has failed to address the problems causing untold misery and damage to financially vulnerable consumers across the UK."

Payday lenders have recently been making progress towards sharing more up-to-date information. Firms including Wonga recently announced they are to start using a new real-time information sharing service which is being launched by credit reference agency Callcredit.

Another major credit reference agency, Experian, has also recently unveiled plans to launch a new service to give credit providers an instant snapshot of someone's financial information.

The Competition Commission recently released a progress update, in which it said it had found that less than two-thirds of payday loans were fully paid back on time or early.

The FCA has previously outlined proposals for clamping down on the industry, including limiting the number of times payday lenders are allowed to roll over loans to twice, forcing them to put "risk warnings" on their advertising and limiting the number of attempts lenders can make to claw back money if there is insufficient cash in a borrower's bank account to two.

The regulator is also looking at capping the total cost of credit.

Russell Hamblin-Boone, chief executive of short-term lending trade body the Consumer Finance Association (CFA), said: "Our members have a good track record of actively referring customers to the major debt charities, including StepChange, as a part of their commitment to responsible lending. So we would expect to see an increase in calls.

"Data from CFA members shows they receive less than five complaints, upheld or otherwise, for every 1,000 loans.

"Independent research shows 94% of their customers pay back their loans on time but we will continue to fund and work with debt advice agencies to help people who get into financial difficulty."