Up to 5,000 protestors calling for David Cameron to resign took to the streets of London on Saturday, surrounding a hotel where the Prime Minister admitted in a speech that he had handled the Panama Papers affair badly.

At one point people were prevented from entering or leaving the Grand Connaught Rooms, where the Tory spring forum was being held amid a heavy police presence. Some demonstrators jumped on a car, showering it with fake money and chanting slogans about tax avoidance.

However Mr Cameron himself was thought to have left the venue before the protestors, who had earlier gathered outside Downing Street, arrived.

Some demonstrators pledged to stay on Whitehall until Mr Cameron left office.

One protestor, Will Forrest, 21, a student from Manchester, told The Independent: “I think he should resign, I think that’s exactly what’s called for.

"If Cameron were to resign, you’d see the infighting between the Tory candidates, the Conservative Party would be at each other’s throats, there would be total disarray.

“If he resigned as a consequence of these protests there would be huge momentum. That’s when people would start calling for a repeal of the [five year] fixed term Parliament Act and a snap election.

Protesters gather outside the gates of Downing Street before moving towards the venue of the Tory Spring Conference (PA)

“It’s going to sound like a cliché, but the people hold the power at the end of the day, there’s only so long you can stay in the streets for before they have to do something.

“Labour and SNP politicians should be putting the pressure on inside Parliament, and we bring the pressure to Downing Street outside Parliament."

Another among the crowd, Dominic Corfield, 25, a teacher from Manchester, said the row over Mr Cameron's tax affairs felty "like a ‘straw that broke the camel’s back’ moment".

“It feels like the first time in quite a while that it could be historical, there could actually be something going on, time will tell… if this is the first day or the only day. If this is the first day, maybe something will happen," he said.

“I’m very angry with the way things are going, but I think this could maybe be a moment, and I think it’s something you can’t miss."

However, unlike others in the crowd, he said he did not think Mr Cameron should resign but instead called for him to crack down on tax avoidance.

Police form a cordon around the Grand Connaught Rooms where the Tory Spring Conference is being held today as protesters gather for the 'David Cameron: close tax loopholes or resign!' demonstration (Rex Features)

“I’d rather see him use his position to make the changes but do I have faith he will do that? Absolutely not," Mr Corfield said.

“The question is, what happens if he does go? What comes then, Osborne, Johnson? Would that be better? It’s not like there is a better more liberal, centrist Conservative alternative to Cameron. The only people who could step in are people who have been with him every step of the way.

“The only way he’ll go is if he’s forced out by his own party, but I think there will be people trying to do that. But he’s backed into a corner now, and I think he’ll fight, both his own party and the opposition. The momentum here is great, but what comes after Cameron goes is the dangerous part.”

David Cameron pig sculpture besides Downing Street (Rex Features)

After marching to the Grand Connaught Rooms, most of the protesters made their way back down to Downing Street to take part in an afternoon of activities, which included speeches by celebrities and TV personalities.