Image copyright Dogs Trust Image caption Roy, a 10-year-old Jack Russell, could not be reunited with his owner due to an outdated microchip and is now waiting to be rehomed by Dogs Trust Leeds

More than 4,700 stray dogs in the UK couldn't be reunited with their owners last year due to outdated microchips, animal charity Dogs Trust has said.

The charity found 37,283 dogs were left unclaimed in local authority kennels between April 2015 and March 2016.

One in eight were pets that could not be returned as their microchips had not been updated by their owners, it said.

In April, it became a legal requirement for all pet dogs to be microchipped with current contact details.

The results come from the organisation's annual survey of local authorities, which also revealed 3,463 stray dogs had been destroyed in the last year.

Jon Gerlis from the Dogs Trust told BBC Radio 4's Today programme: "We took a poll which found that only 9% of people saw updating their dog's microchip as a priority when they move home - that compares, unfavourably, to updating their digital television set."

"When you move home, a dog doesn't know its surroundings, but it naturally wants to go home, so it's probably the most crucial time in actually making sure that your chip details are up to date - especially if you don't have secure borders in your garden," he added.

Dingle's Story

Image copyright Dogs Trust Image caption Dogs Trust says it will never put a healthy dog like Dingle to sleep

Staffordshire bull terrier Dingle was picked up as a stray in Rochdale, Greater Manchester, around 10 September.

He was kept in a local authority pound for seven days before Dogs Trust Merseyside took him in.

Dingle, aged 12, was microchipped but the contact number registered on the database was no longer in use.

He is now up for rehoming at the centre.

Dogs Trust found the total number of stray dogs handled by councils had decreased by 21% - from 102,516 to 81,050.

Of those handled by councils, 16,447 were microchipped - 9,052 of which were reunited with their owners due to either a chip or ID plate.

The charity said the decline in stray dogs taken in by local authorities could partly be attributed to the change in the law relating to microchipping.

Owners who fail to microchip their pets with up-to-date contact details face a fine of up to £500.

'Still work to do'

Adrian Burder, the charity's chief executive, said: "To discover that the number of stray dogs in the UK is down from last year is promising, but with over 37,000 dogs remaining unclaimed in council pounds last year, it's clear we still have work to do.

"Local authorities work tirelessly caring for stray and abandoned dogs each year, but sadly they just don't have the resources or man power to care for every stray dog in the UK.

"Stray dogs that find themselves at Dogs Trust are the lucky ones, as we will never put a healthy dog to sleep, but not all of the unclaimed dogs are so fortunate."

Dogs Trust said it hoped the new law would significantly bring down the number of stray dogs taken in by councils next year.