Estate agents have been labelled as “ignorant” after failing to properly display leasehold information on listings.

A report by the HomeOwners Alliance campaign group on issues with leaseholds, Homes Held Hostage, looked at a sample of 100 agent listings on Zoopla at the end of March, finding that 51% didn’t list the form of tenure.

The report said: “Only 49% of flat listings specified whether the property was a share of freehold or a leasehold property. Furthermore, only a quarter of the listings were specific about the length of time left on the lease, a piece of information vital for the potential purchaser to be able to make an accurate assessment of value.”

It is not just estate agents who come under scrutiny in the report, freeholders are criticised for excessive charges and delays to provide information during a property sale.

In 2015, leasehold properties accounted for 43% of all new-build registrations with the Land Registry – almost double the proportion of 22% in 1996, according to the report.

Citing a Leasehold Knowledge Partnership report from 2014, the HomeOwners Alliance says there are 4.99m occupied leasehold flats in the UK. Using Government and LKP data, the research then extrapolates that 1.577m of these leasehold flats and houses are owner-occupied.

The report said: “In the eyes of the Government they are home owners, but in the eyes of the law they are little more than tenants.”

Only 58% of leaseholders questioned said they knew the length of their current lease, and of those that did, 24% said that it was under 80 years.

Analysis of these figures then suggests that more than £4bn will need to be paid to freeholders by leaseholders to extend these leases over the coming years.

Among the recommendations in the report are calls for all lease extensions to be a minimum of 250 years and for a ‘peppercorn rent’ to be charged.

Paula Higgins, chief executive of the HomeOwners Alliance, said: “Leasehold ownership can be traced back to the Domesday Book and it is a practice that should relegated to history.

“Unscrupulous and avaricious actors within the property industry are using sharp leasehold practices to line their own pockets and fleece householders.

“Developers and estate management companies rely on leasehold to bamboozle consumers, charge exorbitant administration fees, ever increasing ground rents and render properties unsellable.

“The situation is exacerbated by the fact that many estate agents are themselves ignorant about leasehold and fail to inform and educate their customers properly.

“The Government needs to take urgent legislative action to protect people from these practices, help people who are already trapped and avert a full-blown crisis.”