The move aims to slow the spread of invasive species. Grey squirrels were introduced from North America

It could be Michael Gove’s biggest and bravest mistake. In a nation of animal lovers he has ordered the slaughter of thousands of sick squirrels and deer — including babies.

The environment secretary has told animal care and wildlife rescue centres that sick or abandoned grey squirrels or muntjac deer brought in by the public can no longer be released back into the wild and must be killed.

The order, which takes effect from March 29, has angered animal lovers who have set up a formal protest petition on the parliamentary website, attracting 45,000 signatories in two weeks.

If it hits 100,000 it will trigger a parliamentary debate, with Gove asked to explain why he wants baby squirrels killed.

The move is aimed at slowing