The BBC Trust review comes after pay details were leaked earlier this year, including a three-year deal for Jonathan Ross reportedly worth �18m.

The study will examine how salaries paid to the BBC's top talent compare with the rest of the market.

Consultancy Oliver & Ohlbaum Associates will conduct the review, which will conclude in the spring.

The study will also look at the impact of the BBC's policy on the talent market, and will ask whether it has led to an inflation of salaries elsewhere.

The reported Ross deal was said to have influenced multi-million pound contracts struck by ITV to secure the services of Simon Cowell and Ant and Dec.

BBC director general Mark Thompson defended top talent salaries in front of a Commons select committee last year, saying that a BBC which did not secure big stars would not please the public.