Work on nearby flat disrupting life of tenants

littlerock

My sister lives in a small flat in a large private block in west central London. She has a long lease. The block is owned by one of the major landowners in the area and managed by managing agents. The flats change hands regularly. Recently two one-bedroom flats near her (on the third floor) were purchased by a private owner who has employed builders to knock them into one flat.

The work has been going on for 9 months now, it is going on at all hours, the builders refuse to talk to anyone, leave a mess in the hallways and come and go via the fire escape. They have already broken a water pipe which flooded into another owner's flat. Staff and leaseholders are getting very fed up. They do not know what is being done, who are the builders doing it, and why it has gone on so long. The whole thing seems totally unaccountable.

Anyone making changes is supposed to lodge plans with the Managing Agents but the agents have told her they cannot enforce this, or exercise any control over the building work, that has to be done at the level of the estate. And apparently, as they are internal renovations, they are not subject to planning permission, or at the very least the council (Westminster) is not interested.

She and other leaseholders have written to the managing agents on several occasions, seeking further information but they just wring their hands and say it is in the hands of the block owners (a well known aristocratic landlord's London estate) who is not responding to their requests for some action.

The leaseholders have been told by the agents that if the work damages other owners' flats, they should claim on their own insurance.

Any suggestions on a way forward?