A Warwickshire castle – converted into a holiday home – has bagged the Royal Institute of British Architects (RIBA) Stirling Prize 2013.

Astley Castle was a crumbling ruin before Witherford Watson Mann Architects gave it a £2.5 million modern makeover.

The fortified manor – complete with moat – had undergone a mishmash of alterations since it was built in the 1100s. With these changes in mind, the firm decided against renovating it back to its medieval glory.

Instead, the designers of Amnesty International UK’s headquarters chose to stabilise the property before adding a new layer of history. Astley now has a pale wood and exposed brick interior.

It was the combination of old and new that impressed RIBA’s judges who described the work as resolving the architectural problem of how to “be resolutely of this age while simultaneously embracing the past”.

The manor beat the Giant’s Causeway Visitor Centre in Northern Ireland and Bishop King Edward Chapel in Oxfordshire – as well as buildings in Harlow, Sheffield and Limerick – to the award.

“Astley Castle is an exceptional example of how modern architecture can revive an ancient monument,” said RIBA president Stephen Hodder.

“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.

“Every detail has been carefully considered, from a specific brick pattern to the exact angle of a view, resulting in a sensually rich experience for all who visit.”

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