Billionaire property tycoon Vincent Tchenguiz has defended his company’s management of private retirement homes amid claims that pensioners are being overcharged for rent and services.

The Iranian-born entrepreneur is chairman of the Consensus Business Group, whose companies dominate the sector, housing around 70,000 elderly people.

Pensioners living at properties in 50 developments claim they are paying unreasonable amounts for property managers and transfer fees if they sell or let their home.

At a number of developments, residents have taken over management of their own finances, employing managing agents and seeking cheaper insurance policies. But a spokesman for Mr Tchenguiz’s company said there were no hidden charges and all residents’ queries had been investigated. He said service prices had been adjusted “where appropriate”.

It is thought rent has been reduced at around a quarter of developments where residents complained of overcharging.

Mr Tchenguiz and his brother Robert grew up in Iran after their father fled to the country from Iraq in 1948.

Together with his brother, Mr Tchenguiz held large percentage shares in Sainsbury’s, Mitchells & Butlers and the SCi group, before he set up Consensus in 2001.

His philanthropic efforts include donating $1 million (£617,500) to the Hadassah Hospital in Jerusalem and paying £320,000 for a Damien Hirst skull in aid of Marie Curie Cancer Care and the Ecology Trust. His charitable foundation is worth around £1 billion.

He owns homes in South Africa, France and Mayfair, a fleet of luxury cars and a super-yacht.

Channel Four News reported on Tuesday that the Office of Fair Trading had deemed the transfer fees “unfair” and potentially illegal.

The OFT is believed to be carrying out an investigation into the way the sector works, but declined to comment on direct complaints against Consensus.

Age Concern’s Andrew Harrop said the majority of complaints it had received about overcharging related to Mr Tchenguiz’s group.

He said: “We are very concerned that these charges are not properly regulated.

“Retired people should not have to go to tribunal in order to ensure the charges they are paying are fair. The OFT needs to step in to ensure potentially vulnerable older people are not being exploited.”

A spokesman for Mr Tchenguiz said: “Peverel [part of the Consensus group] has a culture of care and a proven record of delivering an outstanding level of service at reasonable rates.

“Tens of thousands of people are leading a secure and happy life living in the properties we manage.”