THE Roundhouse, the engine shed turned theatre in Camden Town, north London, could reopen if Camden Council sells the building to Keatway Leisure for pounds 895,000. But Equity, the actors' union, has expressed its 'deep concern' at the sale, particularly as a rival bid from Manchester's Royal Exchange Theatre was rejected after it fell pounds 45,000 short of the Keatway offer. In a letter to Equity, Camden says: 'The days of supporting and subsidising the arts without a second thought are long gone', and that it will reconsider the matter if RET can come up with extra funding. Although Equity has intimated that the shortfall could be met from its own trust fund, the sticking point is a commitment by Keatway to spend up to pounds 400,000 on clearing asbestos from an adjacent building, an offer any rival bid would have to match. Equity has called on the Secretary of State for National Heritage, David Mellor, to intervene, and English Heritage will fight any plans to alter the Roundhouse structurally.