The latest project in the transformation of Archway is creating another 150 flats for the area – and because of arcane planning laws not one of them will be affordable.

Instead, the converted offices in Hill House next to the Tube station are being marketed as luxury flats that will set buyers back £500,000 for a studio and £725,000 for a two-bed.

Developer Bode bought the 13-storey office block for a reported £23million in 2014 and is able to convert it into flats without planning permission thanks to a government rule introduced in May 2013. It’s the same clause that allowed the offices at the adjacent Archway Tower to be converted into 118 luxury flats for rent.

Islington Council says since it was introduced, the borough has lost seven football pitches’ worth of office space to these luxury flats and not one has been affordable. Ironically, an extension of just nine flats did require planning permission because it was a new build, and will generate a small handful of affordable homes off-site.

The fact Hill House is “100 per cent private sale” is being used as a selling point, and Bode stands to rake in £65m. But the town hall is not so pleased. A spokeswoman said: “Changes to permitted development rules seek to erode the power of planning authorities to protect office space and secure affordable homes and other benefits.

“When developers are able to bypass the planning process, homes are often poor quality and do not meet the council’s space standards.”

The 2013 law does not yet apply to office space in the south of the borough, where planning permission is still needed. That’s set to be lifted next month, though the town hall has acted by introducing rules that mean planning permission will still be needed.

“The council is extremely concerned about the loss of our ability to secure good quality homes, particularly affordable homes,” the spokeswoman added.

Hill House will also bring new shops at the base of the tower.

Bode did respond to a request for comment.