Dog owners might have to tie up their pets to stop them attacking burglars, police have warned – amid growing controversy over a clampdown on dangerous animals.

The Association of Chief Police Officers say planned amendments to the Dangerous Dogs Act could leave householders 'liable to prosecution' if their dog bites a burglar while they are out.

Ministers want to close a loophole in the law that makes it difficult to prosecute dog attacks that take place on private property.

The move follows a string of attacks on children, postmen, and health visitors on private land.

The proposals will include a defence for people whose dogs attack a burglar while they are at home. But critics warn the defence will not protect owners if a burglar is attacked while they are out, or if the attack takes place in the garden or an outbuilding.

The loophole in the proposals will leave dog owners open to potential fines of up to £5,000 – or even a two-year jail sentence – if their pet attacks an intruder while they are not at home.

Now Acpo, the organisation which represents senior police officers, has warned that the plans will favour burglars.

In a letter to MPs they said the police 'would rather the householder was given a defence in law' to prevent prosecution if a dog attacks a burglar while they are out.