Stringent rules imposed by American Equity, the actor's union, have been bypassed in a deal that enables the West End hit The Real Thing to transfer to Broadway in March with its English cast in tact.

Perhaps because it feels threatened by the worldwide reputation of English actors for excellence, American Equity has for many years blocked the wholesale transfer of London casts to Broadway.

But in a conciliatory move this week, it has reached an agreement with UK Equity to allow The Real Thing to cross the Atlantic next month in exchange for Warren Leight's award-winning play Side Man, just opened at the Apollo, which consists of the entire Broadway cast, plus one new member of the cast, Jason Priestley, also an American, well known from the long-running soap, Beverly Hills 90210.

One reason for the settlement was that both plays have exactly the same number of actors in the cast - seven - thus avoiding quota wrangles.

Ron Kastner, the American producer of The Real Thing, admitted that American Equity are more intransigent on the subject of exchanges than British Equity. 'They simply don't want English actors to take roles that could go to Americans,' he said.

Top producer Cameron Mackintosh has had a number of clashes with American Equity, notably over the casting of Jonathan Pryce as the Eurasian pimp in his US production of Miss Saigon in 1990. When he threatened to cancel the whole thing, Equity relented and after finally opening in April 1991, it recouped its $10.9m investment in 39 weeks.

Trevor Nunn also had a run-in with the union last year after they refused to allow the leading players in his award-winning revival of Oklahoma to transfer, insisting on an indigenous cast.

For Jennifer Ehle and Stephen Dillane, the stars of The Real Thing, a high profile Broadway run is bound to open up other career opportunities.