The import of cats that are more than 42 days pregnant will be banned when new powers come into force.

Leading charities have welcomed the Government’s pledge to crack down on heavily pregnant cats being brought to Britain for sale as pets.

The import of dogs with cropped ears will also be stopped.

The changes will result from the Government giving its support to a new law by vet turned MP Danny Chambers.

Cats have a gestation period of around 65 days. Experts warn that kittens should not be separated from their mothers too early.

An RSPCA spokeswoman welcomed the pledge, saying: “Too many pregnant pets are being imported into the country by people making quick cash from the exploitation of animals.”

She said the new law would protect the creatures from “arduous journeys at a time when they are particularly vulnerable” and help stop kittens being “taken away from their mums too early and sold to unsuspecting members of the public”.

“This law will also stop cats and dogs being imported after painful procedures such as declawing and ear cropping, which are illegal in the UK,” she added. “Being able to import these pets currently can provide a worrying smokescreen for illegal activity at home too.”

Former security minister Sir John Hayes, who pushed for a ban on the import of heavily pregnant cats, welcomed the commitment, saying: “We have a special responsibility, which I always say is God-given, to protect living things that can’t defend themselves from human carelessness or cruelty.”

Ben Parker of Battersea Dogs and Cats Home agreed that the ban is an important step forward.

“For years, we have campaigned for stronger protections for animals and a clampdown on illegal, low-welfare animal imports, and we welcome the inclusion of this measure within the Bill,” he said. “This legislation is an important step in tackling such practices that harm animals, and we hope it progresses swiftly through Parliament.”

Mandy Hobbis, co-founder of the charity CatsMatter, said: “Tighter controls on imports will help vulnerable cats from being exploited and we must make it as difficult as possible for those wishing to disregard the welfare and safety of mothers and kittens... This Bill builds on efforts to enhance our world-leading standards of animal welfare and is another action that makes it clear that the UK aims to crackdown on loopholes in our animal welfare legislation.”

Setting out how the Government plans to use the new powers, Environment Minister Daniel Zeichner said: “We will use these powers to prohibit the bringing into Great Britain of cats that are more than 42 days pregnant. We are fully supportive of this Bill and would like to see it pass through both Houses as soon as Parliamentary time allows.”