Set up in 2001, it was the forerunner of 20 gateway or foundation medicine programmes now run by UK universities.
Medical schools have faced severe criticism that they recruit disproportionate numbers of students from private or selective schools, leading to a lack of diversity in the profession - and these courses are among measures gradually bringing change.
The King's extended course was initially limited to students with academic potential from non-selective schools in parts of London without a tradition of sending pupils to medical school but since 2017 it has recruited across the UK.
Up to 90% of students are from black and minority ethnic backgrounds, with a similar proportion from households with annual incomes of less than £40,000, predominantly the first in their family in higher education.
Co-director Professor Steve Thompson says the course has the express aim of "levelling the educational playing field.
"It's a cornerstone to King's commitment of giving back to society and making the world a better place," he says.
He is clear that the medical profession should better reflect a population who "aren't all white middle class."
"Patients feel more comfortable telling you something if they feel a connection with you," says Dr Valentine. "I'm not saying it's not possible to do that with any good doctor but, you know, there's no need for it to be full of a certain kind of person."
Paying it forward
For Yousef, his goal of qualifying as a doctor is in sight. It hasn't always been easy, there have been pre-exam panics, even though he's now in the top 15% of all students across both the standard and extended courses and is about to embark on a master's degree in global health policy.
"It's been crazy to be honest," he says. "I've been through a lot. I've changed a lot, I would say had ups and downs... I really thank God." If he gets the breaks, he says, he would love to work in a hospital serving the area he grew up in.
He feels his Newham roots have given him a richer outlook on life and will, ultimately, make him a better doctor. He still lives there and sees his friends from school regularly. "It's still my community, my people and I'm proud of it."
This article has been republished with permission from the BBC.