A report from the Government's panel on Fair Access to the Professions found applicants who attended private schools or who are from wealthy backgrounds are more likely to be recruited into top law, media, banking and even civil service professions.
The report found staff who were privately educated dominate the workplaces in more than half of these sectors - but these people represent only 7% of society.
Alan Milburn, former secretary of state for health and currently MP for Darlington, chaired the panel. He said: "Bright children from middle-class families as well as those from poorer backgrounds are missing out on top professional jobs. Many professionals are working hard to put this right but their efforts need to be intensified."
And a spokesman from recruitment website ClickAJob added: "It might be an old tradition but the school tie network still carries weight and influence. More often than ever it is who you know that is important, which means canny professionals without the same background should look to compensate with their own connections to ensure they are competitive."
The top jobs still go to members of the old school tie network
High-flying jobs in the UK have become almost closed to those without family connections and middle class backgrounds.
