Organised by the RIBA Competitions Office, the contest is the brainchild of innovative cultural agency Grizedale Arts, which has built up a reputation for backing pioneering arts-led project across the Lake District.
Entrants are asked to design a 'removable structure which will allow the castle [and its keep] to be used for concerts and public performances.'
This project forms part of an ambitious regeneration strategy for the town of Egremont, in west Cumbria, and is funded by West Lakes Renaissance and Arts Council England.
It is also supported by the Egremont and Area Regeneration Partnership as part of the Creative Egremont public art strategy.
The first stage will be judged anonymously, after which three chosen finalists will be asked to develop their initial concepts.
Each stage-two competitor will receive an honorarium of £2,000.
For further information on how to enter please contact the RIBA Competitions Office on (0113) 2341335 or visit www.architecture.com/competitions.