Judge Kathryn Kimball Mizelle, who was controversially nominated by President Trump as a judge for life at the age of just 33, said a “blanket restriction on firearms possession in post offices is incongruent with the American tradition of firearms regulation”, The Hill reports.

Restrictions “abridge the right to bear arms by regulating it into practical non-existence”, she said.

Her ruling came in a case concerning a US Postal Service (USPS) driver who was arrested and charged after bringing a gun onto USPS property.

The driver will no longer face a trial on a charge of illegally possessing a gun in a federal facility, but can still be tried for forcibly resisting arrest.

Postal workers in the US have a troubled history with firearms. The phrase ‘going postal’ refers to a spate of mass shootings by postal workers from the 1980s onwards.

At one point in the late 1990s, postal workers made up less than one per cent of the US workforce but were responsible for 13 per cent of workplace homicides.