The chairman-elect of learning disability charity Langdon has warned supporters of the potential impact of local-authority cutbacks on its services.

Addressing the 300 guests at its dinner in central London on Monday, Jonathan Joseph explained that in the wake of Chancellor George Osborne's austerity measures and the imminent Care Act, the charity anticipated a 10 per cent fall in local-authority income, which currently accounts for around £3.75 million of the charity's £5 million budget. If the fears were realised, Langdon would need its donors to make good the shortfall.

"I need to ask you to exceed your very high standards of generosity," he said. The £400,000 raised on the night will go towards an employment programme, social and recreational activities and "Jewish ethos" work at Langdon, which was founded by four parents who could not find an organisation to help their children with learning difficulties to lead independent lives.

Langdon has appointed a Jewish ethos manager who will encourage members to engage with their Judaism and increase their involvement with the wider Jewish community. "Langdon's key purpose is to empower independence," Mr Joseph said. "Every member of Langdon is a source of tremendous pride to us. We live for their successes."

Newsnight presenter Emily Maitlis was the headline guest, hosting the charity's awards and posing for photos with the winners.

"We have seen how extraordinary Langdon people are," she said. "They have succeeded against all odds to lead full, happy and ordinary lives - lives that would not have been possible without this wonderful charity, and your support. Without Langdon their life would be bleak, often hopeless."

The broadcaster - who has been involved with Langdon for a number of years - said afterwards: "It is a really warm-hearted charity. I always get the most amazing reception.

"This is somewhere I can put names and faces to the work being done. And I think that's a really lovely way to be involved with something."

Daniel Bourla, who has a speech impediment and mild learning disabilities, won the Excellence in the Workplace award for his successful employment record and for travelling to and from work independently. "I didn't expect it, not in a million years," the 25-year-old said. "Langdon made me more independent and more confident. What I like best about working is being busy."

His mother, Sharon Bourla, praised Langdon for enabling him "to have an independent life like any other young person".