Six buildings have been shortlisted for the 2015 Riba Stirling Prize, British architecture's highest accolade. Now in its 20th year, the prize recognises the UK's best new building. The winner will be announced on Thursday 15 October.

The shortlist features a school, a social housing project, a cancer care centre, luxury apartment towers, a university library and an art gallery extension. IBTimesUK looks at each of the buildings on this year's shortlist.

Burntwood School, Wandsworth, London. Architect: Allford Hall Monaghan Morris. Contract Value: £40,900,000.
A huge south London girls' school with light-filled classrooms and generous corridors. The judges say: "Burntwood has the collegiate air of an Ivy League campus – perhaps it's all the pale, finely detailed concrete, perhaps it's the elegant covered walkway that links the principal buildings, drawing together the disparate styles and ages of the architecture."

Darbishire Place, Peabody Housing, London E1. Architect: Niall McLaughlin Architects. Contract Value: £2,300,000.
A 13-home Peabody social housing apartment block near the Tower of London. The new building replaces a mansion block taken out in World War II by a V2 bomb. The judges say: "This is a brilliant piece of urban design. The use of materials and form means that the new building complements its neighbours without mimicking them."

Maggie's Lanarkshire. Architect: Reiach and Hall Architects. Contract Value: £1,800,000.
An oasis of calm retreat in a previously alienating and unsympathetic environment – the corner of a hospital car park. The judges say: "The surrounding perforate wall of handmade Danish brick offers a degree of separation from the nearby hospital grounds. Stand on the rear terrace and you can see the houses opposite, walk down the steps into the courtyard and they and the rest of the world are hidden."

Neo Bankside, London SE1. Architects: Rogers Stirk Harbour + Partners with John Robertson Architects. Contract Value: £132,000,000.
New luxury housing towers with exo-skeleton and external lifts on the site of old warehouses on London's South Bank. The judges say: "Neo Bankside is seductive architecture. This is high-quality housing you would be unlikely to see elsewhere in the world in the inner city – and it is ungated.

University of Greenwich Stockwell Street Building, London SE10. Architect: Heneghan Peng Architects. Contract Value: £38,900,000.
This building houses the main university library and the departments of Architecture, Landscape and Arts. The judges say: "This is a building that will inspire future generations of architects. The building is full of light and generous spaces and benefits from clear vertical circulation – the acoustics are remarkable. A nicely done gallery addresses the street inviting the public in, as do the shop and café. This is a very public university building."

The Whitworth, University of Manchester. Architect: MUMA. Contract Value: confidential.
Extension to the 19th century Whitworth Gallery on the edge of Whitworth Park in Manchester. The judges say: "The worst of the 1960s additions to the 19th century gallery, such as suspended ceilings, have been stripped out and earlier spatial relationships reinstated; the gallery now embraces the park."

The winner of the 2015 Riba Stirling Prize will be announced on the evening of 15 October at the Royal Institute of British Architects (Riba) in London.