A children's playground built on top of an east London nursery school is in line for a prestigious award.

The Rooftop Nursery in Ottaway Street, Hackney, was designed by a team at WHAT_architecture with a brief to create a cheap childcare space in the inner city in order to help get local mothers back to work. The designers were determined that the building would not be simply functional.

Completed in 2005, it is lined with granulated rubber so children can play without risk of getting hurt. The scheme is one of those nominated for the 2007 London Regional Awards, chosen by the Royal Institute of British Architects.

The judges said: "This is a cheap, fun, inventive solution to inner-city childcare.
"The project has been helped by the dedication of the architects who identified the site, helped get funding and designed the nursery. It is a real asset to its community in many senses."

Other schemes in line for awards are on a far grander scale. They include Arsenal's Emirates Stadium in Islington, the new Barbican Centre and the restored Roundhouse in Camden Town. The winners will be announced tonight.

Andrew Hanson, chairman of the Institute's London region, said: "The list demonstrates a wealth of talent across a wide spectrum of projects, ranging from imaginative design for private houses and community centres, through sensitive restoration work, to a range of spectacular larger buildings. "The judges will have a tough task making their selections." Judges have also nominated the "brilliantly" schemed Broadwater Farm Children's Centre.