07/04/2014 11:54 BST | Updated 04/06/2014 06:59 BST

Techstars London Diary: We Are Your Family Now

"Running a startup is like being punched in the face repeatedly." I can think of no more accurate phrase to describe the process of running your own business. It's a quote from Paul Graham, founder of startup accelerator Y-Combinator.

The accelerator programme I've just started, Techstars, has so far been a bootcamp of brutal honesty. The punching not only comes from Techstars' own founders, but a daily parade of mentors who have exited or ran successful businesses. It's an intense three-month programme; our onboarding email included the ominous-sounding statement: "Prep your family and significant other. You won't spend much time with them for the next 13 weeks."

Around 1,500 companies applied to take part in Techstars London. After five rounds of Skype interviews and a final showdown involving a room of senior Techstars judges, 11 businesses were chosen, with teams flying in from all over the world - Korea, Israel, America, Spain. We were one of only three teams from the UK that made the cut. Techstars receive equity in every startup that participates. In return they invest a small amount of money in each team and mentor them both within the programme and for the lifespan of the startup.

Perhaps sensing the teams would be full of introverted techies, the teams were split up and sent on a treasure hunt around London, forcing us to interact with each other and spend a day breathing fresh air. As we searched for clues like we were five again on the first day of the most serious three months of my life, I realized the people in the other teams had previously held some heavyweight positions at places like Google, Uber, and Skype. One founder was even a particle physicist on the Large Hadron Collider. (I don't know what this means.)

On day two, the clock had gone forward a few years and we were in school. With 30 seats facing a screen, Techstars director Jens Lapinski addressed us, the pupils: "I've put my serious shirt on today." What followed was a forensic examination of why and how most startups fail. Like every other founder in the room, I was thinking: 'I won't be one of the ones that fails, though.' I just laughed out loud reading that back to myself. Every founder says that, of course, yet even the venture-backed U.S. startups have a 3 in 4 chance of never returning investors' money. Most, if not all, of the startups watching the talk will finish the Techstars programme by pitching for investment at the end of the three-month program. It's the focal point of just about everything. Pitch or die.

With that in mind, week two is all about meeting people who have either done what you've done before, or have lots of money to invest in people like you. You have 20 minutes to pitch, gather feedback, and receive 'mentor's whiplash' from the sheer amount of feedback you get. You could be meeting six or seven mentors in a morning, all of which usually have impressive but vaguely intimidating LinkedIn profiles. Some are the very same investors who may give you money in less than three months' time. We were asked questions like "What makes your startup special?" and "What problem do you solve?" The mentors are there to help you, even if it sometimes feels a bit like the Alec Baldwin speech in Glengarry Glen Ross.

The 'Boot Camp' analogy is often used within the office we all share, given that the startups in the program are all going through long hours and intense days. With eight of the 11 teams moving to London from outside the UK, there's a family vibe manifesting itself through in-jokes and group picture messages, from teams who are often thousands of miles from their families. I'm feeling it too, and I only live down the road in Shoreditch.

We were told by the Techstars founders who accepted us into the programme: "No-one wants to be an entrepreneur. If someone came to us and said they did, we probably wouldn't let them in the programme." It's vaguely sadistic that we do a job where every day we find out pretty much everything we're doing is wrong or could be improved, and that working over 12 hours a day may increase our chances of success from 0 to about 1% (my co-founder Lewis said that one, but I think it makes sense). Even at those odds, at 9pm most nights the majority of the teams are still at their desks. There are no hipster CEO's on beanbags with iPads here. We may be stars come Demo Day, but the grind is only just beginning.