Dog owners face fines of several hundred pounds if they fail to microchip their pet following a change in the law.

But Scottish owners are the least likely to microchip their dogs – only 56 per cent of them, the lowest percentage out of ten UK regions, according to Gocompare.com.

It is now a legal requirement in Scotland for all dogs to be microchipped and registered on an approved database by the age of eight weeks. Anyone caught flouting the law is given 21 days to comply or face prosecution and a fine of up to £500.

The microchip is tiny – about the size of a grain of rice – and is inserted under the loose skin on the back of the dog’s neck. Mini microchips are also available for small breeds. The chips contain a unique identification number, which is registered on a database and holds the owner’s contact details.

The measure is intended to improve animal welfare by quickly reuniting lost or stolen dogs with their owners. More than 100,000 dogs are lost or stolen each year, according to the Kennel Club. Sadly, about 6000 are put to sleep because their owner cannot be traced. Campaigners also hope the new law will reduce the number of abandoned animals and curb the black market trade in dogs.

The picture shows Max, a microchipped English Springer Spaniel who has been missing since Christmas Day 2015 from Stoke Lacy in Herefordshire, and now has a group of almost 9000 Twitter followers helping to find him. "His family are truly devasted, especially his best friend and owner Erin who is two years old and believes he has gone to chase rabbits," says campaign helper Stephanie Edwards. "The positive which has come from this is that many dogs have been reunited with their owners with the help of Max's dedicated troops."

The change in the legislation could affect hundreds and thousands of dog owners. Only 60per cent of dog keepers in the UK know for sure that their pet is microchipped, according to Gocompare.com.

Of the top 20 dog breeds, English Springer Spaniels and Golden Retrievers are the most likely to be chipped, at just over 70per cent. However, just 45per cent of Pug owners said their dogs had been microchipped, making them the least chipped breed of the top 20 most popular dogs, including all mongrels.

A vet can usually microchip your dog and the typical charge is between £15 and £30. Some local councils will also offer the service or you can a free appointment at one of the Dog Trust’s two Scottish rehoming centres, in Glasgow and West Calder.

Microchipping is usually harmless and painless, but your dog could be exempt if a vet certifies that microchipping could adversely affect the animal’s health.

Your dog only needs to be microchipped once, but it is the owner’s responsibility to keep the details up to date, perhaps if you change address. You should also make the appropriate amendments if you sell or give your dog to someone else.

Failure to notify the database of any changes could again result in a £500 fine. Ben Wilson of Gocompare.com, the comparison website, says: “Any database is only as good as the data it holds. So if you move home or sell your dog, you also need to make sure that you update your registration details to reflect this change.”

The new law could lead to a drop in pet insurance premiums. Mr Wilson says: “Encouraging all dog owners to get their dogs microchipped is a very positive step. Not only will it help improve the chances of lost dogs being returned to their owners, it could also reduce the number of dogs being stolen and this may lead to lower pet insurance premiums if there are fewer claims.”

The number and cost of pet insurance claims reached record levels in 2015, according to the Association of British Insurers (ABI). Pet insurers paid out £657 million in claims last year, up 9per cent on the previous year. The number of claims at 911,000 also went up by 9per cent. The average claim is now £720, about three times the average pet insurance premium at £241.

However, the new legislation has raised concerns that pet insurers will refuse to pay out claims if a dog is not microchipped. The ABI advises all customers to check with their insurer, but Direct Line insists that failure to microchip a dog will not invalidate the cover. The company also has no intention of passing on any information to the police. It does however support microchipping as a way to promote responsible pet ownership.