Fundraising must be governed by high standards and ideas, not organisational or individual self-interest, the Commission on the Donor Experience has said as part of 526 suggestions it has made to improve fundraising.
In a report published today summarising the work of the 18-month project, which was sparked by the fundraising scandals of 2015, the commission calls for fundraisers to treat donors with respect in their language and fundraising practices and says pressure, persistence and undue persuasion are not the right approaches.
The report says many fundraising leaders lost sight of what they could and should be doing to consistently deliver an exemplary experience for their donors and other supporters.
"So deeply ingrained is the short-term, target-driven culture across fundraising in the UK that significant numbers of practising fundraisers, their leaders and their agents still struggle to genuinely understand this," it says.
Research commissioned to accompany the report found that nearly a quarter (23 per cent) of the 1,040 people surveyed felt they had been emotionally blackmailed by charities. Qualitative research accompanying the survey found that participants felt fundraisers were over-reliant on emotional language and appeals were seen as manipulative.
Participants said they understood why charities used emotional appeals, but many said it often left them powerless, upset or frustrated when they were unable to donate.
To avoid this, the commission said such appeals should focus on the beneficial power of the charity, rather than the gravity of the problem they were trying to solve.
One in five (20 per cent) said their experience of engaging with charities they already supported was as good as it could be. This fell to 12 per cent for charities they did not already support.
Almost two-thirds (63 per cent) found their experiences of dealing with a charity they already supported were good, and per cent said the same of their experiences of charities they did not already support.
Only 10 per cent said they did not have an example of a "best experience" of fundraising, such as being thanked sincerely, asked politely, being made to understand the impact of their donation or being respected when they said no, according to the report.
But only 13 per cent said they had not had a "worst experience", which meant 87 per cent of donors had experienced issues such as feeling harassed, asked to give more than they could afford or being left feeling guilty for not being able to give more.
Lewis said in a statement: "Our research shows that profound change is needed and charities need to give supporters genuine choices.
"It is time we stopped thinking about what not to do, and more about what to do better, ensuring that donors feel really great about their giving.
"That is why the commission is making this call to action to charities and asking them to think seriously about the promises they can make to donors."