Citizens Advice received 4,600 complaints about letting agents last year – 4% up on the previous year.

The charity has also hit out at what it calls “inexplicable fees” charged by agents.

The complaints included disputes about fees, quality of service and the handling of customer money.

Citizens Advice also said that some agents and landlords are flouting the law on tenancy deposits, and that “enforcement and redress when things go wrong are patchy”.

The charity expressed considerable concern about the private rented sector as a whole, saying that its advisers dealt with over 300 problems every day last year.

Altogether, it said its bureaux dealt with 444,000 housing-related inquiries last year, but the most common problems when it came to tenure related to private rented accommodation.

Repairs and maintenance, rents and other charges, and problems with tenancy deposit protection were routinely reported.

The report says: “We also see many problems relating to eviction, including landlords taking action for reasons other than rent arrears.”

The report, called Consumer Challenges 2015, insists that retaliatory evictions are “a common story”.

The report’s section on housing concludes: “Britain’s private rental sector bears all the hallmarks of rapid growth.

“Nearly twice as many people rent privately as ten years ago and many now rely on the sector for a long-term family home.

“A patchwork of protections is being slowly extended in some areas, but most renters remain uncovered, lacking rights we take for granted elsewhere.

“At Citizens Advice we see the consequences of this in the more than 300 problems reported to us every day with privately rented accommodation: renters evicted because they asked for a repair, renters charged high and inexplicable fees by their letting agent, and renters struggling to secure redress after something has gone wrong.

“In 2015 we will be continuing our research into the problems renters face and the lessons that could be learned from wider consumer policy to ensure private renting can provide a safe and settled home.”