London: Burglars attacked by a dog as they break into an unoccupied home could receive thousands of pounds in compensation while the pet’s owner is sent to prison.

Under the proposed Dangerous Dogs Amendment Bill, which will shortly be put before MPs, it will become illegal for an owner to allow a dog to attack a lawful visitor such as a postman or nurse. But it will also mean that owners could face prison if their dog attacks a burglar while they are out.

Dogs charities will this week raise concerns about the bill, which specifies that a homeowner will be exempt from prosecution if a dog attacks a burglar or trespasser only if the owner is “in or partly in a building or part of a building”.

The Dogs Trust, an animal charity, said: “We are extremely concerned that the draft bill does not provide any exemptions from prosecution if the owner is not present at the time a dog attacks a trespasser.”

Under the proposed legislation, animals face destruction if they attack a visitor inside a house or in the garden, or are dangerously out of control.

Owners could face criminal prosecution, including unlimited fines and up to two years in prison, while the victim could be awarded compensation.

The bill explicitly gives householders protection from prosecution if their dog defends them against intruders in the home while they are present. However, if they are not there, no such protection exists.

Legal advice to the Dogs Trust has also raised concerns about farm dogs that bite trespassers or attack a thief trying to steal equipment such as quad bikes or tractors when the farmer is not present.

Guard dogs that are allowed to patrol private premises without their owners being present could also face destruction if they attack burglars climbing over a fence. The owners would face the prospect of a prison term.

Trevor Cooper, a solicitor specialising in dog law, said: “The intention of this bill is that lawful visitors have protection from injury if they are going about their duty but this bill penalises dogs which are defending the home from intruders.

“The way the bill is drafted means that an offence would be committed if the owner isn’t present. That isn’t right — it’s not fair on both the dog and the householder.

“If you have gone out to the shops to buy a newspaper and your dog attacks a burglar or trespasser, you will have committed a criminal offence.”

The Department for the Environment, Food and Rural Affairs said it did not believe the police would arrest householders if their dog attacked a burglar while they were out. “No dog owner whose pet attacks an intruder breaking into their property while they are out would ever face prosecution by the police [sic],” it said.