 One of the conditions of the 1982 competition was that the new wing had to include commercial offices as well as public gallery space . However , in 1985 it became possible to devote the extension entirely to the Gallery 's uses , due to a donation of almost £ 50 million from Lord Sainsbury and his brothers Simon and Sir Tim Sainsbury . A closed competition was held , and the schemes produced were noticeably more restrained than in the earlier competition . 
