The first housing block made from stacked Y:Cube units could be seen in Merton by early next year if a planning application is approved tonight.
Plans for 36 housing units stacked in a three-storey block in Woodstock Way could provide an affordable housing solution to YMCA and social housing tenants in Mitcham.
Designed by architect practice Rogers Stirk Harbour and Partners, each Y:Cube is a 280 sq ft house containing a bedroom, kitchen/living room and bathroom.
Each unit costs £30,000 to build and will be let for £140 a week - 65 per cent lower than the market rate.
Andy Redfearn, YMCA London South West’s director of housing and development, said: "I'm feeling nervous. It's a really big deal because it's the first one of its type in the UK and we have got a number of other local authorities interested.
"So this is a huge, huge decision for the YMCA for potential to roll out around the UK. There's been a lot of political interest and so we want to get this first site done."
If approved, work will begin in October with new residents due to move in next February.
The decision comes six months after a striking red prototype was unveiled outside the YMCA in The Broadway, Wimbledon.
YMCA residents and journalists are among those to have slept in the Y:Cube, with Wimbledon's Liberal Democrat parliamentary candidate Shas Sheehan the latest to try it out.
Mrs Sheehan said: "I enjoyed it. There are a few comments that I fed back to Andy Redfearn and I think fundamentals of the idea are really excellent."
She would like to see better access for disabled residents, a larger bathroom sink and the eradication of "dirt traps" she identified in the housing unit.
She said: "I did manage to get a good night's sleep. It was really very comfortable.
"I think it's really excellent and could really help solve the problem of transition for YMCA residents. I think it's a great, imaginative way to help solve the problem of housing supply."
"It was really comfortable": Shas Sheehan after a good night's sleep in the Y:Cube
Mr Redfearn said the prototype in Wimbledon has since been revised by architects, with changes including larger sinks and disabled access and amenities for ground floor housing units.
The application will be considered by Merton Council's planning committee at a meeting in Merton Civic Centre this evening.