London councils are blocking one in four applications to turn offices into homes, new research has revealed.

Figures compiled by planning firm Daniel Watney and seen by Property Week show that 457 prior approval applications for office to residential conversions were made across London in the three months to June 2014. Of those, 25% were refused, 56% were granted, and 19% were deemed not to need prior approval.

Redbridge Council had the highest number of refusals, at 75%. In contrast, Barking & Dagenham, Bexley and Enfield approved all of their applications.

The research marks the first time approvals have been broken down borough by borough. Last month, figures released by the Department for Communities and Local Government showed that across the country, 1,900 office-to-residential applications were received by councils, with 900 approved — a 47% success rate.

The number of rejections was cause for concern, said Charles Mills, partner and head of planning at Daniel Watney. “Councils are still finding ways to refuse office-to-resi conversions and in some cases, with good reason,” he said.

“It could be due to developers supplying insufficient information or the development could have a negative impact on the local area,” he added.

But at the same time, we have a woeful under-supply of new homes and remodelling old buildings for new use is far more environmentally friendly than building them from scratch.”

Responding to council fears that the conversion of offices to residential dwellings could result in a loss of employment space, he said: “Protecting office space is important where there’s a need, but it’s important councils avoid using this as a stick to play party politics with.”

Since May 2013, when changes were made to permitted development rights, developers have been able to convert offices to residential use without seeking planning permission.

However, they still have to seek prior approval, defined by the government as “approval from the local planning authority that specified elements of the development are acceptable” before the work can proceed.

Prior approval applications can be refused if they don’t adequately address transport and highway issues, contamination and flooding risk, with developers needing to ensure there is enough information submitted.