By Ollie Stone-Lee
Political reporter, BBC News website
Every picture tells a story. And often the most memorable are not the stories politicians intended when they tried to illustrate their gleaming new policy with a nifty photo-shoot.
Aides say Margaret Thatcher was a natural for the cameras
The thirst for new ways of grabbing extra publicity will rage ever more fiercely as we approach the general election expected next May.
Previous polls have provoked some of the most inventive, disastrous and downright silly photo stunts in British politics.
It is not just the politicians who get in on the act. The 1997 contest saw Tony Blair continually taunted by a Tory activist dressed as a chicken, who in turn was harangued by a fox and chicken hired by the Daily Mirror.
Conservative Cabinet minister Lord Hailsham produced some of the more outlandish earlier picture opportunities at party conferences.
In 1957, he happened to mention to the press that he would be swimming from the Grand Hotel the next morning.
They were surprised when he was sighted not only in a bathing suit and robe but armed with flippers and a snorkel.
"I had a pleasurable bathe every day before breakfast, to the delight of the press," Lord Hailsham wrote in his memoirs.
He insisted the incident had not been premeditated but the pictures of him ringing a bell at the end of party conference or biting into a giant stick of rock show he was more than ready to play up for the cameras.
In today's climate, politicians may be more wary. At least one press officer who has watched Tony Blair at close quarters has commended him for his caution about doing anything unplanned at a photo call.
The prime minister knows some photos have haunted entire political careers, not least his predecessor as Labour leader, Neil Kinnock.
It must have seemed as if nothing could go wrong when Kinnock took a stroll in front of the cameras on Brighton beach with his wife Glenys at the 1983 party conference.
The footage of him trying to dodge an incoming wave only to fall over in the surf looked blundering enough at the time but Spitting Image prolonged the agony by using them every week in its title sequence.
Lord Kinnock recently blamed his wife, saying: "She was wearing new boots. Grey. Very nice. I, being the gentleman I am, stopped her falling over, not the other way round."
The baseball cap picture dogged William Hague
William Hague was another would-be prime minister who suffered the hangover of an ill-chosen picture stunt just as the public were getting to know him.
The famous baseball cap emblazoned with his name which he wore on a theme park water ride was wheeled out for every article criticising the Tory leader.
Commentator Simon Heffer wrote that he looked "like a child molester on a day-release scheme".
Joe Haines, press secretary to the Harold Wilson, says he left arranging photo shoots to other staff but was concerned to prevent unwanted pictures.
He says: "I always made sure Harold was not photographed with a drink in his hand or with somebody who was disreputable."
Photo opportunities have helped politicians' images too.
Tony Blair recruited Kevin Keegan to underline his youth
Pictures of John Major on his soapbox in the 1992 election underlined his man-of-the-people efforts.
Tony Blair reinforced his image as a youthful, sporty leader in 1997 with his memorable ball-heading contest with Kevin Keegan.
And ex-Liberal Democrat leader Paddy Ashdown did little harm to his macho reputation when he leapt into an oil rig training pool in 1999 and helped "rescue" Scottish colleague Jim Wallace.
Perhaps the leader to have capitalised most out of the picture opportunity was Margaret Thatcher.
She showed an eye for an eye-catching, animal friendly picture in the 1979 election campaign when she quickly started hugging a calf - even if it is said her husband Denis remarked: "If she doesn't stop cuddling that calf, she'll kill it."
The Sun newspaper apparently suggested Mr Gummer's photo call
At a time when defence issues offered a popularity not seen now, Baroness Thatcher confirmed war leader status by appearing wearing goggles and a Grace Kelly white scarf in a tank during a visit to Germany in 1986.
A man used to both ends of a lens, photography-mad Labour MP Austin Mitchell, says photo calls do not inevitably go wrong.
But he warns: "A malevolent photographer can turn a photo shoot into total chaos or the opposite of what was intended."
Lady Thatcher has herself admitted not being immune to the inevitable mischief making among press snappers.
In her memoirs, she recalls being caught out by the press during a visit a Devon farm in the 1983 election.
"I was standing on a heap of cut grass and the Daily Mirror photographer asked me to pick some up," she writes.
"I saw nothing wrong with that, and so I obliged. He took his photograph - and the picture duly appeared the following day with the caption 'Let them eat grass'. It does not do to be too cooperative."
Many run-of-the-mill photo calls are taken for granted
The press office for Agriculture Secretary John Gummer was perhaps too helpful when it agreed to a newspaper's requests he prove his family's eating habits had not changed during the BSE crisis by eating beef for the cameras.
Photographers were invited to an Ipswich boat show to watch him and four-year-old daughter Cordelia doing just that.
The resulting photos were much criticised, not least because from one angle Mr Gummer looked as if he was force-feeding his daughter as he held the burger while she took a bite.
He later told ex-BBC journalist Nicholas Jones he held the burger because it was too hot for Cordelia to handle.
Nonetheless, the damage was done. A Private Eye front cover imagined one of the cameramen saying: "The public won't swallow this" and Cordelia replying: "Neither will I."
Sometimes it is politicians themselves who unprompted turn a run-of-the-mill photo call into a story in its own right.
John Prescott blew up a storm in 1998 when he joked about Peter Mandelson's attempts to get onto Labour's National Executive Committee at an event meant to publicise wildlife friendly flood defences.
Holding up a jar housing a Chinese mitten crab, the deputy prime minister teased: "You know what his name is - it's Peter.
"Do you think you'll get on the executive, Peter?"
The number of "pincer movement" jibes in the press did not bode well as Mr Prescott stood in for the holidaying prime minister.
Such howlers are much rarer than the mass of photo calls used every day to brighten up what may be a rather routine story or announcement.
But they are the kind of incident likely to make all but the boldest politician a little camera shy in front of trigger happy photographers.
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