Oxford Architects is embroiled in a High Court tussle with Cheltenham Ladies' College over unpaid fees.
The Technology and Construction Court claim is thought to relate to a £3 million art and technology building completed in 1999.
The project, which replaced a redundant boarding house, comprises five floors of art studios, workshops and food technology laboratories.
The building won a Cheltenham Civic Trust Award in March 2000.
Oxford Architects' brief also included a full accommodation and curriculum audit carried out in 1994.
The practice hit the headlines at the beginning of the year when its £18 million animal-research facility at Oxford University was dogged by threats from animal rights extremists.
Property belonging to Oxford Architects was reportedly vandalised, and construction was halted after activists targeted contractor Montpellier. by Clive Walker