Langdon this week became the first Jewish charity in the UK to produce a report measuring the social return on investment, charting the impact of every pound spent.

Using a methodology standardised by the Cabinet Office, the learning disabilities charity said it had been able to show that it “achieves an impact equivalent to £9.05” for every £1 donated.

“The social benefit does not just apply to the Langdon member, but to the other people involved in the member’s life, such as their parents and siblings, as well as the wider society, such as local authorities and co-workers,” said a spokesman.

The charity has said recent cuts in statutory funding means it now “has to raise 20 percent more just to stand still,” so the timing of the report is significant.

“This groundbreaking review is a part of our continued effort to maximise the impact of the fabulous support Langdon receives from its donors,” said the charity’s chairman, Jonathan Joseph.

“It also reminds everyone that by supporting our members, they are also making a significant difference to the lives of those around them.”

In measuring social return on investment, the charity looked at the confidence, independence, isolation and mental health of service users and their families, noting that “the ripple effect of Langdon’s services is that parents feel more secure and confident about their child’s welfare, and siblings feel an easing of responsibility for long-term care plans for their [sibling]”.

A recently-commissioned report by the Institute of Jewish Policy Research revealed there were more than 23,000 Jews in the UK with a learning disability, around eight percent of the Jewish population.