Leaseholders on the council’s flagship new estate have been told their £685,000 flat is effectively worthless, because the town hall can’t confirm it meets safety regulations brought in after the Grenfell tragedy.

About 200 other homeowners on the Kings Crescent Estate - which was completed in January 2018 - could be left in the same position when they renew their mortgages.

The council has apologised to the couple affected who are now "trapped" and unable to sell the home opposite Clissold Park because no mortgage provider will get involved without reassurance it meets current cladding and insulation safety standards.

They were devastated when they were told by their broker the surveyor deemed the flat had a "£0 present condition value" without a form signed off to say it meets safety standards. After 10 weeks of being "given the run-around" trying to obtain it, they are questioning why the council can't complete the simple form. They are now paying double what they should be for their mortgage as a result.

"Surely the council hasn't constructed a flagship development that doesn't meet the new regulations - this is a complete outrage," they said.

"The broker wants information on whether it's standard, safe and secure, and they won't fund the property if they think it's at risk of burning down, and with all the different fires, in Grenfell, Barking and Worcester Park, I understand their concerns." A council spokesperson said they are confident the 273 home development would meet current safety regulations, which were amended in December and prohibit the use of "combustible" cladding and insulation in high-rise residential buildings over 18m high.

But they could not confirm to the Gazette that they do. Mayor of Hackney Philip Glanville said: "The new homes at Kings Crescent were built in accordance with building regulations that applied at the time of construction so meet all the required safety standards, and have had fire risk assessments completed in the last 12 months.

"This is an administrative issue caused by a lack of clarity about how changes in regulations should apply to existing buildings, and does not mean that there is any fire risk caused by the materials or construction of the building. It is a complex issue affecting the house building and mortgage industry as a whole."

The couple's mortgage broker told the Gazette: "I've never come up against something we haven't been able to overturn, unless the building has been genuinely structurally unsound, and that's when a client is trying to buy something from auction that's falling down. From day one it's been a mystery why are they being so difficult about it."