Nearly 25 kilos of matzah meal, more than 650 boxes of matzah, 6,000 eggs and 180 bottles of Palwin No 10 will help feed 200 Nightingale residents in what chief executive Leon Smith believes is "the biggest Pesach operation in the country".

The south London home runs six Seders, requiring hundreds of new utensils, including 180 Seder plates. Pesach preparation involves the specialist cleaning of six dining rooms, a huge kitchen, café and staff dining room.

Mr Smith oversees much of the process, along with deputy catering manager Rita Hunter. "We start planning Pesach straight after Chanucah, ordering food, planning menus and cleaning," he explained. "Food costs increase by up to 15 per cent.

"Staff training is really important, because most of them are not Jewish. So we have to make sure people understand the story and why we need to do what we do.

"They work extra hours and we get in specialists to clean the light fittings and windows. The kitchen is deep cleaned by a company which works overnight. It's mayhem in here the day before - all the utensils are replaced and we kasher everything with boiling water."

Making sure residents felt comfortable during the upheaval was vitally important, Ms Hunter added.

"After the actual care, the most important thing to them is food. They are not shy in sharing their opinions of it.

"A change in diet can be difficult for residents who are very frail. They might not 'get on' with matzah. So we make rolls from potato flour."

The different Seders "depend on what residents feel able to do", Mr Smith explained. "The most active will have a full Seder, the ones with severe dementia get Seder 'highlights'."

Another issue was that religious observance varied greatly among residents.

"We are a microcosm of the community, so some are very religious and some just feel comfortable in this environment. Last year I was sat next to a lady who said it was the first Seder she had been to since she was a child."

The home needs to raise extra money to cover the expense of Pesach and makes a seasonal appeal for donations.

As with other welfare organisations, Nightingale is facing the threat of funding cuts from local authorities. "Some want to cut as much as six per cent of their funding for residents and it's just not sustainable," Mr Smith said. "It's still very much up in the air, although it should have been agreed on April 1. The only reason we can afford to keep expanding is the generosity of the community."

Around two-thirds of the residents have dementia and the average age is 89. A £6.5 million dementia facility for 40 residents, the Wohl Wing, is nearing completion and is set for its official opening in July.