Ashya King, 5, is suffering from a brain tumour and has been snatched from Southampton General Hospital

Police are desperately trying to track Ashya King, believed to be in France, over serious concerns his life may be at risk.

He was taken by his parents Brett King, 51, and Naghemeh King, 45, from Southampton General Hospital against doctors' wishes at around 2pm on Thursday, August 28 and they were seen boarding a continental ferry from Portsmouth to Cherbourg with Ashya and his six siblings, which arrived at 8pm last night.

Ashya cannot communicate verbally and is immobile and is likely to be in a wheelchair or buggy.

Police believe if he is not found today there are serious concerns for his life due to his illness.

He was receiving 24-hour medical care in Hampshire after undergoing surgery recently as well as other ongoing medical issues.

Detective Superintendent Dick Pearson of Hampshire Major Investigation team said: “If we do not locate Ashya today there are serious concerns for his life. He is receiving constant medical care within the UK due to recent surgery and ongoing medical issues.  

"Without this specialist 24 hour care Ashya is at risk of additional health complications which place him at substantial risk.

“He needs to be taken to a medical facility for his urgent health requirements as soon as he is located.

“We have also launched a social media appeal and would urge everyone to share this appeal, particularly if you have friends and relatives in France and bordering countries.”

The family, of St David's Road, Southsea, were travelling in a grey Hyundai I800 Style CRDI, registration KP60 HWK (similar to above) and police believe they remain in France.

Hampshire Police is working with its counterparts in France on the search and the latter has activated its emergency child rescue alert protocols to locate the family as soon as possible.

In a video posted on YouTube last month, Naveed King said his little brother Ashya had been diagnosed with a brain tumour and was undergoing emergency surgery.

 Speaking into the camera in a message directly to Ashya, he said: ''I haven't slept. I've been awake all night worrying.

 ''We love you so much. We're all here for you.

 ''Everyone is praying for you. We just want to see your smile again.

 ''No kid at the age of five deserves to have a brain tumour. Let's just hope the doctors know what they're doing and they know exactly where to operate and what to take out, and they take everything out and you can be better.

 ''And when we look back in 10 years' time when you're 15, we can actually see that things have changed for the better. Just because they're bad at one point doesn't mean they'll always be bad.

''I love you so much. I can't wait to see you.''

He added: "Hopefully the doctors know what they are doing and they know exactly where to operate and what to take out and they take everything out and you can be better."

In another video, Naveed visits his brother in hospital, bringing him a number of toy cars to play with.

It clearly shows Aysha connected to a number of machines monitoring him.

Anyone with information which may help locate Ashya King should contact Hampshire Constabulary as soon as possible on 101 quoting Operation Aquilion.