Heath had just inherited a Britain reeling from Wilson’s disastrous economic performance, and cuts were demanded in every department.

The Treasury demanded Thatcher, then Minister for Education, make departmental cuts of £9m (£125m in today’s money). Free school milk cost £14 million per year (almost £200m today), twice what was spent on textbooks.

The previous Labour government had already abolished free milk in secondary schools in 1968, so Thatcher reasoned it would be a logical step to roll the scheme up further, and that the Education budget should be utilised to build new schools rather than deliver what she considered social services.

However, despite the Treasury demanding total axing of the milk scheme, Thatcher lobbied to continue offering free milk to the under-7s and special needs schools.

Thatcher had not anticipated the intense emotional response to the policy, and needed a full police protection unit whenever she visited schools. The row was so intense and so vividly remembered by Thatcher that in 1989 she immediately shut down Ken Clarke’s proposal to shut the remaining scheme down to save £4m (£11m today). Even later, the Cameron government was persuaded to abandon plans to shut the scheme down in 2011, despite costs having risen sharply to £50m (£75m today).