Missing dog: Jack Russell jumps out of car window on Severn bridge

Louise Boss in her vehicle with Jack Russell, Mouser

A dog owner is appealing for help to find her missing Jack Russell who managed to open a car window and jump out in queuing motorway traffic.

Louise Boss did not immediately realise Mouser had got free while on the Prince of Wales Bridge over the River Severn between Wales and England.

She thought he was in the boot before pulling over to find him missing.

"I can't bear to think of him on his own - it's driving me crazy," said Ms Boss, from Barry, Vale of Glamorgan.

Mouser went missing at about 18:30GMT on Tuesday.

"I heard the window come down but had no idea he had jumped out," she said.

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She believed Mouser managed to open the electric window and told him to "get down" while she closed it.

'I called and called - he was gone'

"It was dark and raining and I had to concentrate on the road," she said.

Ms Boss then realised it was quiet and "assumed he had got in the boot".

"I called and called, then pulled over - he was gone.

"My other dog was still in the car."

Dog gone: Mouser is brown black and tan in colour and is chipped, along with a contact number on his collar

Ms Boss said her son joined police officers trying to find Mouser after witnesses told them that he was seen heading towards the Welsh side of the bridge.

"He's only a year old. He's very nervous and won't approach people," said Ms Boss.

"I'm praying someone picked him up. I don't even know if he is hurt.

"I'll never take any dog in the car without restraints again," said Ms Boss, in an online appeal for help.

A spokesperson for the National Highways said it notified patrolling traffic officers after missing Mouser was reported.

"We also checked CCTV cameras and unfortunately neither ourselves or Gwent Police could detect the missing dog.

"We received no further reports from motorists last night, we have received no further reports of sightings today, and we do hope the dog is repatriated with its owners."

The Highway Code requires animals being transported in vehicles to be "suitably restrained" and it suggests using a seat belt harness, pet carrier, dog cage or dog guard.