Professions such as law and medicine are increasingly beyond the reach of those from all but the wealthiest backgrounds, according to a report into social mobility.
The report, Fair access to the professions, was the result of work by a cross-party panel on social mobility, and its findings will be presented to Prime Minister Gordon Brown by the panel's chairman, former minister Alan Milburn.
The report calls for greater monitoring of the social background of those entering professions, in the way that figures are published for race and gender.
It also criticises informal recruitment systems, such as internships and work placement, as becoming a back-door for better-off, better-connected youngsters.
Milburn said said that top professions "have become more and not less exclusive over time".