It was not in the script and briefly sparked panic among the army of Tory aides accompanying David Cameron's every step around the country.
But in a dramatic encounter on a south London pavement yesterday, the realities of everyday life burst into the most heavily choreographed election campaign in British political history. The Conservative leader was heading for his car after a meeting at which he demanded action against the "broken society" when he was confronted by Jonathan Bartley and his seven-year-old, wheelchair-bound, son, Samuel.
Surrounded by camera crews and photographers, Mr Bartley launched a tirade against Tory policy on special needs education. He protested that the Conservatives wanted to "reverse the bias towards the inclusion of children in mainstream schools".
Mr Bartley went on: "At the moment there is a bias against inclusion, not a bias for it, as your manifesto says. You talk about the broken society. It nearly broke up our family getting our son into school."
Clearly taken aback, Mr Cameron knelt down to insist that that was not his policy – and that he had personally written the section of the Tory manifesto dealing with the issue.
He also told Mr Bartley of his battle to find a place in a special school for his profoundly disabled son, Ivan, who died last year at the age of six.
"I absolutely promise you that I would never do anything to make it more difficult for children to go to a mainstream school," the Tory leader said. "At the moment, people don't get what they want. You didn't get what you wanted, I didn't get what I wanted. We both had to fight."
Mr Cameron eventually got in his waiting limousine, while aides took Mr Bartley's details for Tory officials to try again to persuade him of their case.
Mr Bartley, the director of the religious think-tank, Ekklesia, said: "I think they were perhaps expecting a sort of friendly chat – I don't think they were expecting that kind of encounter and those points being put, but I think it's important because it doesn't seem as if David Cameron has received that perspective from many parents."
Later, on board his battlebus as he toured Labour marginal constituencies in the North-west which he will have to overturn to win power, Mr Cameron said: "The current way the law works, and I experienced this for myself, is you are not always told about the alternative options to mainstream schooling." Touring Bury, another area with two target Labour marginal seats for the Conservatives, Mr Cameron plunged into a Mill Gate market.
He posed for photographs on mobile phones for schoolchildren, bought a black pudding for £1.67 and pressed the flesh with shoppers. He also kissed the first baby of the campaign, Sienna Rose Quinn, aged four months. She was wearing a knitted cardigan with a hood. "Hug a hoody," said Mr Cameron, returning to his theme of "Broken Society".
Her father, Mark Quinn, 34, a worker in a logistics centre, is one of the many undecided voters Mr Cameron has to persuade if he is to avoid the hung parliament he warns against.
Mr Cameron remains haunted by the possibility of Nick Clegg, the Liberal Democrat leader, forming an alliance with Labour after polling day to keep the Conservatives out of power. But he was in good humour about the reports of plots to replace Gordon Brown with his ally, Ed Balls. "Vote Clegg and it's Balls," said Mr Cameron.Reuse content