A London gallery built to house the private art collection of artist Damien Hirst has won the Riba Stirling Prize, the UK's leading architecture award.
The creation of Newport Street Gallery saw the remodelling of three listed Victorian industrial buildings and the building of two new ones in Vauxhall.
Winning architects Caruso St John were also shortlisted in 2000 and 2006.
The Stirling Prize judges called their work "a bold and confident contribution to the best of UK architecture".
"Caruso St John's approach to conservation is irreverent yet sensitive and achieves a clever solution that expresses a poetic juxtaposition of old and new," they said.
"The collection of buildings is beautifully curated, pulled together by the use of brick yet still expressive of their individuality. The playful use of LED technology gives a contemporary addition to the facade.
"Internally, the five buildings are connected as a continuous and coherent sequence of light filled gallery spaces. The simple and logical circulation is enlivened by exquisitely detailed and sensuous staircases."
The judging panel - which included Rachel Whiteread, the first woman to win the Turner Prize - said the gallery was "a generous asset to an evolving community".
Find out more about the shortlisted buildings:
Jane Duncan, president of the Royal Institute of British Architects (Riba), praised Hirst for making "an exceptional contribution to the UK's strong history of private patronage of architecture".
She said: "Not only has Damien opened up his enviable private art collection to the world, but he has commissioned a real work of art to house it in.
"Caruso St John have created a stunningly versatile space from a number of linked buildings, with beautifully crafted staircases and superb details including tactile brick facades that blend with the street externally and create a succession of wonderful gallery spaces.
"This project exemplifies the best of UK architecture - a highly considered and creative project that brings to life a previously unloved pocket of the city."
Hirst said the gallery had "realised [his] ambition to create an unobtrusive and beautiful series of buildings that work perfectly as a space to exhibit great art".
"I am immensely proud of what we achieved and the reaction it has received in its first year of opening," he added.
"It's rare for architects to be given the opportunity to realise a personal vision of the quality of the Newport Street Gallery, and for that vision to have a generous public dimension," said Peter St John of Caruso St John.
"We see the building as a palace for direct, intimate and luxurious encounters with contemporary art, and we are very pleased that this award will bring more people to see this extraordinary collection."
A partly underground house, three educational buildings and a London estate redevelopment were also shortlisted for this year's prize.
The first of these won a BBC News poll to find readers' favourite building on the shortlist - while the Newport Street Gallery came last.