Cheap Labour !

In US TV dramas Brits are everywhere.Many Britons are recruited to play American characters. TV audiences might be wondering why. Speak to some producers working in US television and they will admit cost is an issue. British producer Andrea Calderwood, who worked on Generation Kill for HBO, agrees that cost is an issue.
"American producers are going for the best talent. Obviously there is an element of cost involved. Once you become an established actor in the US, you can command huge prices - so people are looking for fresh talent that doesn't cost that much."

Dominic West , appearing in The Wire , put this forward for the explanation "More value-for-money, that's really what it is. If they wanted someone experienced and I was American, they'd pay a lot of money - and I'd be better known, I suppose. We're cheaper."

English actor James Purefoy, who played Mark Antony in Rome, believes the network of British actors is perceived by American colleagues as cheap labour. "We are often referred to in Los Angeles as white Mexicans," he told an audience of British hopefuls at a seminar on how to make it in America.

No more than the humble factory worker , actors are a commodity where the price of their labour power determines their worth