The report is based on interviews with a representative sample of 1,000 people over the age of 16, conducted three times a year since 2001. The results show that the proportion of respondents who volunteer has remained static at 19 per cent in the past 12 months, but has fallen from the 20 per cent figure of 2004.
Since 2005, the Government has spent millions of pounds trying to increase volunteering among young people through initiatives such as v.
The research shows an increase of two percentage points in the 16-24 age group, from 14 per cent in 2005 to 16 per cent in 2007. Among those who volunteered, the number of occasions on which they did so dropped from 48 in 2005 to 45 last year.
The proportion of people aged from 55 to 64 who volunteered dropped from 20 per cent in 2005 to 16 per cent in 2007.
"The Government's broad message that volunteering is a good thing to do hasn't been effective," said Joe Saxton, co-founder of nfpSynergy. "We need more initiatives targeting specific groups."
But a spokeswoman for v said that the figures might not show the full picture because many young people did not associate certain activities with volunteering. "If you ask a young person who coaches an after-school sports team whether they volunteer, they might say no, either because they don't associate this with what they are doing or because they don't see the word 'volunteer' as cool," she said.
A spokesman for volunteering charity CSV also questioned the findings. "Our figures for 2006/07 show there was a rise of 3,000 people volunteering through CSV," he said. "Similarly, figures for our Retired and Senior Volunteer Programme show that interest in volunteering among older people is strong, with an average increase of 1,000 volunteers a year."
He added there was even a waiting list for some "cutting-edge" volunteering opportunities with organisations such as Crisis and the North York Moors National Park.
The survey results are at odds with the Government's latest Citizenship Survey, which shows that, between April and June 2007, 73 per cent of all adults volunteered. It also shows that overall levels of volunteering have not changed since 2001, but that formal volunteering has risen from 39 per cent in 2001 to 45 per cent in 2007.
A spokeswoman for the Office of the Third Sector said: "Investment in adult volunteering is at an all-time high, at £82.2m for this year, up from £16.6m in 1997/98."
One initiative after another
2001: The Government sets up the Experience Corps to increase volunteering among the over-50s. It ends its support for the initiative in 2003, after spending £20m.
2005: Year of the Volunteer is launched to recruit a million new volunteers. There are themed months, starting with health. The initiative is coordinated by CSV and Volunteering England, with £1m from government.
2005: The Russell Commission recommends a government-funded youth volunteering charity that involves young people. In May 2006, v is launched to recruit a million young volunteers by 2010.
2006: The England Volunteering Development Council launches the Commission on the Future of Volunteering, chaired by Baroness Julia Neuberger. It will report shortly.
2008: A parliamentary inquiry into volunteering among 18 to 24-year-olds is due to begin. The independent, cross-party inquiry will be chaired by Labour peer Baroness Morgan.