Donations by retirees could rise by 50 per cent, partly as a result of changes to pension arrangements, the final report of the Commission on the Voluntary Sector and Ageing has predicted.

Decision time, the final paper from the Commission, published today, says donations from those over 65 could shoot up by half over the next two decades.

By 2033 nearly a quarter of the UK population will be aged 65 or over, with charity donations by that age group reaching £3.49bn a year, an increase of £1.18bn from 2013, the report predicts.

The report also suggests that the value of charity volunteering by the same age group could hit £15.72bn a year, an increase of £5.32bn.

In the paper, the Commission argues that the ending of compulsory pension annuities will unlock considerable assets held by the baby-boomer generation and that the charity sector is failing to strategise comprehensively to take advantage of the windfall.

The paper says that charities are suffering a “collective failure of imagination” towards the ageing population, and too often treat ageing as “just a question of what to do with more older people” who need services, rather than as an asset.

"The baby boomers will seek out organisations that share their values, can demonstrate a measurable impact, and which give them a real role in driving change—increasingly blurring the boundaries between donor, volunteer and beneficiary," the report states.

"Charities should ensure fundraising staff have the right skills and experience to connect with donors across the age spectrum—an age diverse workforce and listening to supporters are vital."

The Commission says that voluntary organisations should review their fundraising strategies to ensure that they offer opportunities for increasingly "engaged and savvy supporters" to become a genuine part of the organisation.

The paper also suggests that sector bodies including NCVO, Navca and Acevo should develop action packs to help their members act and take the lead on age-proofing their own activities.

The Commission was established by New Philanthropy Capital (NPC) and ILC-UK to promote awareness of ageing in the voluntary sector.