Emergency plans are in place to immediately evacuate more than 20 vulnerable dementia sufferers from a Wimbledon care home in crisis.

The measures are under consideration by Merton Council amid reports of drastically declining standards of care at Lancaster Lodge, after it emerged last week the home was to be shut down by operator Craegmoor in just seven weeks.

A snap inspection of the home was conducted by the authority on Tuesday following allegations made over the weekend of staff failing to turn up to work and sick residents not being tended to appropriately.

Council officers and Wimbledon MP Stephen Hammond have demanded written assurances from Craegmoor – operator of more than 250 homes nationwide – that staffing levels would be maintained until the home’s closure.

But one resident’s relative, who did not wish to be named, said: “I was there over the weekend and it was absolute chaos.

“I told the manager if just one person dies I will be going straight to the coroner to give evidence.

“They were cripplingly short staffed and noone seemed to know what was going on or who was in charge. There was one resident just sitting there looking so seriously ill I shouted ‘Get her an ambulance’. Only then was she tended to.”

Last week Sarah McQuitty, whose 86-year-old mother Patricia Dean lives at Lancaster Lodge, said: “Being forced to move could kill some of these residents.”

An anonymous member of staff said: “The dedicated nurses and carers, as well as residents of the home, were in a shock to hear the sudden news.

“All the staff at the home are stressed looking for jobs, some don’t turn up on duty as they’re searching for work. The few on duty are working under pressure and this has affected staff as well as elderly residents’ health.”

Helen Cook, head of assessment at Merton Council social services department, said residents would only be withdrawn from the home in Lancaster Avenue in a worst-case scenario.

She said regular inspections of the home would be conducted to ensure care standards were maintained until its closure.

Mr Hammond said: “Craegmoor has a duty of care. These are people who are elderly and vulnerable and they are entirely reliant on the care they receive. There’s real concern about how they were told of the closure, the period of notice given, and how they are able to find a new home. Even if Lancaster Lodge is going to close the standards of care must be maintained.”

A spokesman for Craegmoor said: “The health and well-being of residents remains our first priority. It is in the interests of everyone concerned with the closure of Lancaster Lodge it is reported fairly and accurately.

“We can confirm the home manager was on planned annual leave over the weekend and support was available for the home from a senior manager during this time.

“Two members of staff were absent on Sunday, however, there was sufficient staff cover at all times.”