An inquiry into the influence of the pharmaceutical industry on the NHS by the Commons select committee on health will begin this autumn.

It wants to examine any conflicts between the commercial drive of the large and wealthy drug companies and the need of the NHS for well-researched medicines.

The inquiry follows concern over the alleged suppression of data from clinical trials involving children given anti-depressant drugs.

When a government working group saw the data from trials of Seroxat in children, they recommended the drug, and all others in its class except Prozac should be banned from use in children because they did not work and side-effects included inducing suicidal thinking.

The committee will look at drug innovation; the conduct of medical research; the way companies promote their drugs; and the evaluation of the efficacy, safety and value for money of drugs.

Richard Brook, chief executive of the mental health charity Mind, said: "We have been expressing unease over the power that drugs companies possess for some time."