A second Stirling prize for Hadid

Zaha Hadid, the Iraqi-born British architect whose designs have struggled until now to gain acceptance in the UK, last night won the country's top architecture award for her first major work here. Her Evelyn Grace Academy, a secondary school specialising in sport in Brixton, south London, was awarded the £20,000 Riba Stirling Prize.

The Academy was the surprise winner: what has come to be known as "The Pringle", the saddle-shaped velodrome with the world's fastest cycling track, designed by Hopkins Architects for the London 2012 Olympics, had been tipped as favourite to receive the accolade.

Ms Hadid's £37.5m school building, made of glass and steel, is squeezed into a site just one-sixth of the average school site, with a 100-metre running track taking pupils to the front door. The president of Riba (the Royal Institute of British Architects), Angela Brady, who chaired the judges, said: "This is a design that literally makes kids run to get into school in the morning. I'd like to think all schools could have that effect."

Ms Hadid said: "Schools are among the first examples of architecture that everyone experiences and have a profound impact on all children as they grow up. I am delighted it has been so well received by all its students and staff."

It is the second year in a row that Zaha Hadid Architects has been awarded the prize, and the first time that a school has won. Last year, the firm won the award for its MAXXI museum of 21st-century arts in Rome.

Despite being one of the world's leading architects, Hadid – whose staff wore T-shirts bearing the legend: "Would they call me a diva if I were a guy?" at the opening of the Cincinnati Contemporary Arts Center in 2003 – had not completed a major building in the UK until this year. Her 1994 competition-winning design for the Cardiff Bay Opera House was abandoned by the Millennium Commission after opposition to the design from local lobbyists. Previously, her firm had designed a Maggie's Centre in Scotland, and, since the academy was completed, the Riverside Museum in Glasgow has also opened. Construction has also finished at Hadid's Aquatics Centre housing the London 2012 Olympic swimming pool and diving centre.

The other finalists for the prize this year were the Royal Shakespeare and Swan Theatres, in Stratford-upon-Avon, by Bennetts Associates; Museum Folkwang in Essen, Germany, by David Chipperfield Architects; office space The Angel Building in Islington, north London, from Allford Hall Monaghan Morris; and the Irish language, arts and culture centre An Gaelaras, in Derry, Northern Ireland, by architect O'Donnell + Tuomey.

The winner, announced last night at the Magna Science Adventure Centre in Rotherham, which itself won the Riba Stirling Prize in 2001, will be broadcast on a special edition of BBC 2's The Culture Show today.