But the Department of Health yesterday pledged merely to “continue exploring how best to achieve a return on taxpayer investment”, offering no date to revisit the four-year pledge.

The apparent climbdown comes after doctors’ groups vociferously opposed a mandatory four-year NHS tie.

The British Medical Association argued that “taxpayers get a significant return on their investment from the dedicated service provided by all doctors over the course of their career”.

The union added that such a policy would discourage students from poorer backgrounds from becoming doctors, and was “potentially discriminatory to women who are more likely to take a career break”.