Photography by Landmark Trust

The RIBA Stirling Prize 2013 for the best new building of the year has gone to Astley Castle in Warwickshire, by Witherford Watson Mann Architects.

Astley Castle is a modern holiday home inserted into the walls of an ancient moated castle. The 12th-century fortified manor had been a ruin since a fire gutted it in 1978 and was on the Heritage at Risk Register. The architects stabilised the ruin to create an original and contemporary new house.

RIBA President Stephen Hodder said: “Astley Castle is an exceptional example of how modern architecture can revive an ancient monument. It is significant because rather than a conventional restoration project, the architects have designed an incredibly powerful contemporary house which is expertly and intricately intertwined with 800 years of history.”

Other winners announced last night include Carl Turner Architectswho won the RIBA Manser Medal for the best new private home for The Slip House in Brixton, which was also shortlisted for the Stephen Lawrence Prize. The Stephen Lawrence Prize this year went to AY architects for their Camden project, Montpelier Community Nursery.

In addition, Wilkinson Eyre Architects won the RIBA Lubetkin Prize for the most outstanding work of international architecture outside the EU by a member of the RIBA, for Cool Conservatories, Gardens by the Bay, Singapore.