Matt Lucas kept 550 guests laughing on Monday evening at the Nightingale Hammerson dinner at London’s Guildhall.

And the charity’s treasurers were also happy, with proceeds exceeding £1 million, in particular to support a major redevelopment at Hammerson House in north London.

Kicking off a programme which also included speeches by Master of the Rolls Lord Dyson, Nightingale Hammerson chair Harvey Rosenblatt and chief executive Leon Smith, Mr Lucas joked: “Obviously, you wealthy, successful people are probably invited to a lot of charity functions. But when it comes to Nightingale Hammerson, I’m seeing a lot of faces here who will be ending up there quite soon. So really, my message to you tonight is to think of this less as a donation and more as an investment.”

Mr Rosenblatt told guests that, having spent £14 million on Nightingale’s Clapham premises over the past four years, the intention was to put £25 million into upgrading Hammerson House.

“Our long-term strategy is based on the fact that there is an undeniable link between the provision of first-class care and modern, spacious accommodation. We plan to increase the capacity at Hammerson to 110 rooms, enabling us to care for an even greater amount of the community in need.”

He added: “Specialised dementia and residential care, together with humour, chutzpah and the unexpected, combine to give us that special edge. We are determined to encourage a more purposeful existence.”

Tributes were paid to chief executive Leon Smith, who stands down next week after 40 years of service to the charity.

Mr Smith spoke of the many changes he had witnessed since joining as a Nightingale trainee. Most notable was that people were living much longer — leading to far more cases of dementia — and that residential care homes had shed their stigma.

Matt Lucas returned to thank Lord Dyson, who spoke about his legal career. “I thought he was going to do a Hoover demonstration, so there’s not a lot I can say now that’s relevant,” he deadpanned. “Apparently, he’s Master of the Rolls. Well, I had the granary and it was delicious, so congratulations.”