Elderly people and parents with buggies may be left virtually housebound for almost three months while their lift is out of action.

Camden Council is about to renew the lift, serving six floors of Chalford House, above Iceland in Finchley Road, Swiss Cottage – and the work will take 12 weeks.

Stair lifts will be installed on each staircase so people who cannot manage the steps can still get in and out.

But a stair lift can only take one person at a time and cannot take buggies or shopping trolleys.

Retired legal secretary Dora Harris, 74, said: “I could cope with being housebound for two weeks but that is the maximum.

“What if there is a medical emergency? There are at least two people with heart conditions.

“There is nothing wrong with our existing lift. It has had a few breakdowns but it is still working.”

At first it was estimated the work – which includes renewing the lift cart and operating machinery and installing new electrical supplies – may take between 18 and 21 weeks, but this has now been revised down to 12 weeks.

Other residents believe the disruption is worth it in order to get a more reliable service. One woman, whose husband has multiple sclerosis and lives on the sixth floor, said the work was necessary.

Cllr Julian Fulbrook, Camden cabinet member for housing, said: “A replacement lift is being installed as part of a programme of work to all our estates to improve reliability and provide a better service for our residents.

“Many lifts are the original ones from when the blocks were built and it is not possible or cost effective to continue to repair them.”