Ding, dong. The doorbell rings twice before a blue light flashes. The two-minute countdown to pitch your business idea into a camera attached to a five-storey derelict stairwell begins.

Over the past few months thousands of budding entrepreneurs have headed to the disused stairwell, located behind a Starbucks on a main road in Twickenham, south-west London.

He hopes to transform it into the headquarters of his company, Helpbnk, a 75,000-person online community that rewards people for helping others.

But while he has been waiting for planning permission to turn the staircase into a pop-up for entrepreneurs, he has put a doorbell on the building and has encouraged people to pitch their ideas.

“Everyone thought I was mad to buy it, but it symbolises something to me – if you want your dreams to happen then it’s just a step by step process,” he told the BBC.

“I want people to realise their potential and I want to give them the tools to have a better life.

“It’s blown my mind how many people have turned up to pitch an idea, just this morning there was a queue outside the door.”

One entrepreneur Simon has recently supported is university student Reiham, who runs a journal company.

She pitched her idea in September and subsequently received £800 funding and marketing help from Simon to get her business off the ground.

Journaling helped her mental health and she wanted to help others with self development, she said.

As well as financial support, Simon also helps connect entrepreneurs to investors, mentors and customers.

Twins John and James Makanjuola, who run a cleaning business aimed at university students, pitched their idea a few months ago, thinking “we have nothing to lose so we might as well go and also clean the staircase when we go to prove how good we are”.

The 22-year-old brothers have received support and advice from the Helpbnk community and said “all we wanted was an opportunity to put our business out there and the rest is history”.

They told the BBC they started their cleaning business after university as they wanted to raise enough money to be able to visit their father, who lives in Nigeria.

“Our family have had homelessness issues and there are lots of things we have not been able to afford so we had to think of something that would get us out of that situation and this is where our business was born,” they said.

Simon, who now lives in north London, was made homeless aged 15 and did not have a support network at the time to help him.

When watching the doorbell videos, he says he “knows how hard it is to ask for help”.

“So when people open up about their past and share their backstory it really touches me,” he adds.

Simon said that was what often inspired him to support someone.

This was the case with Kellie Roberts, who pitched her dog grooming idea and spoke about the difficulties of starting a business.

She was given £6,000 to start her mobile pet grooming service in London and said the opportunity had left her “inundated with opportunities and clients”.

Despite the gloomy winter weather, people of all ages from all across London are making their way to Twickenham to ring the doorbell and be in with a shot of turning their business idea into a reality.

As passers-by look on bewilderingly at the queue of people standing outside a derelict stairwell, Simon says it is all about “taking risks and dreaming big”.

And that is certainly what many are doing today.