To shock or not to shock? It is a question that constantly confronts charity marketers. The use of harrowing imagery in advertising campaigns can overcome apathy and bring prominence to a charity and its cause, but it also risks offending or outraging the public, potentially alienating donors and undermining the charity's aims.
Amnesty International UK, Barnardo's, NSPCC, the National Autistic Society and the British Heart Foundation (BHF) are among the charities that have made waves by using shock advertising in recent years. Yet with so many going down this route, some marketing strategists have begun to wonder whether the public will become immune to the technique, or worse, come to regard it as nothing more than a cynical ploy to grab attention?
There are signs that some charities are weighing up a change in direction.
For example, since 1996 Amnesty has used a hard-hitting creative work to explain how everyday objects such as irons and pens can be used as implements of torture by brutal regimes.
But the latest Amnesty mail pack adopts a gentler and more personal approach, telling the story of a Tibetan nun who has been imprisoned by the Chinese authorities for singing freedom songs. The work is to be tested against the established donor recruitment packs and, if the results are favourable, may signal a shift in Amnesty's marketing strategy.
Another charity experimenting with a softer approach is HopeHIV, which provides support to African children who have lost their parents to Aids.
It has developed an ad with agency Bartle Bogle Hegarty which shows a little girl dancing in a graveyard but which ends on a hopeful note.
"I define our ad not as a shocking one but one that has surprise in it,
says HopeHIV's director Adrian Gosling. "What it doesn't do is offend sensibilities.
"Our brief was to get away from the flies-in-the-face image, which is frankly quite insulting to most of our friends in Africa. If there is a trend in charity marketing, it is that people are taking a more reasoned approach to addressing issues. Audiences are being treated as intelligent people."
However, it is equally true that advertising is at its most effective when it is simple and direct. Shock tactics, adroitly employed, can be powerful and memorable.
Last week, the BHF courted controversy when one of its hard-hitting newspaper ads was banned by the Advertising Standards Authority (ASA). The ad showed a woman with a plastic bag over her head and bearing the strapline: "I've got heart failure. And this is what it feels like every morning."
The ASA received 238 complaints about the ad, some from parents concerned that children seeing the image might place themselves in danger of suffocation by putting a plastic bag over their own heads. The Royal Society for the Prevention of Accidents branded the choice of image "unfortunate".
Despite the criticism, the BHF is largely unrepentant. It points out that it sought advice from the Committee of Advertising Practice (CAP) on two separate occasions and was told that it did not contravene the advertising codes.
The ad has also been very successful and encouraged 13,500 people to ask the BHF for help and information about heart failure - significantly more than the 238 who complained to the ASA. When the original ad was replaced in the national press by a less shocking image, calls for information fell from more than 2,000 a day to 350.
"The BHF stands by its decision to use a powerful and hard-hitting image to draw much-needed attention to the distressing aspects of heart failure,
says BHF's director of marketing and communications Betty McBride.
Barnardo's has arguably drawn criticism with its advertising more than any other charity in recent times. Two years ago its infamous creative execution of a baby injecting heroin led to a storm of protest. CAP went so far as to assert it was "too shocking
to be shown, although some newspapers ran the ad anyway.
Barnardo's has repeatedly argued that its uncomfortable approach to advertising is necessary to highlight the deprivation and abuse that can blight children's lives. "The images reflect the reality of our work,
says director of marketing and communications Andrew Nebel.
The National Autistic Society has also found that shock ad tactics can be successful, provided the execution is right. Earlier this year, it ran a TV commercial portraying a child repeatedly banging his head against a wall. The aim was to show that some people with autism have a tendency to repetitive, self-harming behaviour and to convey the message that trying to understand autism is like banging your head against a wall.
"Our budget for advertising is really limited, so we had to find a way of getting people's attention,
says the National Autistic Society's marketing and fundraising director Assaf Admoni. "We couldn't have explained the disability in a 30-second summary.
"There is a danger that you can go too far. But we made sure we weren't overstepping the mark - we were careful to test the concept beforehand."
And it appears that the approach has had the desired effect. Tracking research showed that the number of people who claimed to know "something or a lot
about autism rose from below 40 per cent before the campaign to 60 per cent at its close.