We will never know whether, without the interruption from that unfunny prankster, Theresa May would with a heavy cold have got through to the end of her speech to Tory conference without incident. As it is, when serially unfunny Simon Brodkin stepped up with a spoof P45 it set off a chain of accidents, that led to a shambles centred on a person under intense pressure just doing her best.

The incident spooked May, understandably, and a voice under pressure proceeded to fall apart. The letters in the slogan then fell off the wall because, I’m told, the stage was nudged or bumped about in the general commotion of people moving, eventually, to assist when the prankster loitered. The wall of the set is connected to the stage floor obviously. It was all bumped and the magnets, on the other side of the set wall, were knocked and the letters started to fall off. You know what happened next.

But although the main focus is on May’s future, because of the way in which her bad luck underlines the loss of authority since the general election, ministers and aides are also asking how it was possible for someone to get so close to a Prime Minister and not be tackled for at least 30 seconds and some claim longer. It is a fair question.

As a government aide put it: “Why did it take the police 49 seconds to get to the guy and contain him properly? He got close to the Prime Minister but then was able  to talk to the Foreign Secretary, the Home Secretary and the Chancellor. How?”

“It was a police failure of communication,” says a minister. “This can’t be brushed away because the PM had a bad cough,” said another. “What were the police doing?”

Close protection for Prime Ministers is, usually, the responsibility of the Metropolitan Police. The perimeter of the conference is guarded by the local police force, in this case the Greater Manchester Police. Around the conference is a “ring of steel” with heavy scrutiny and airport-style checks on anyone going into conference. That worked.

It was in close protection, in the difficult work done by those guarding the Prime Minister from terrorists and angry protestors, that something seems to have gone amiss. Steve Park, a former police protection officer told the Guardian that something had gone badly wrong inside the hall: “Police are ultimately responsible for what goes on, even if there is a private security company in place to do the check-in and scans,” he said.

“A couple of security personnel should have been close by, and they should have dealt with this professionally, which means removing the guy. I was thinking what the hell is going on here? We’re not talking about anybody here, we’re talking about the government, people that, when they walk around the building, have a contingent of four or five protection staff closely guarding them in a diamond formation.”

Brodkin had a conference pass (which is approved by CCHQ and goes to the police for checking) and he sat in a media area near the photographers next to senior ministers.

One minister speculated that the confusion may have come about because Brodkin looked odd or vulnerable, like a protestor just quietly making a point and they may not have wanted to cause a potentially violent commotion until they worked out what they were dealing with. “But still I don’t see why you don’t rugby tackle him to the ground the moment he tries to go within ten feet of her. And why did they then let him go up to the cabinet afterwards?”

MPs and Number 10 will no doubt want to hear detailed answers from the police when parliament returns.