A British tourist has revealed the filthy conditions inside Thailand prisons as a warning to other visitors.

The 29-year-old ex soldier was held in two Thai police cells and a Bangkok deportation centre for 15 days.

He took photos and videos on a phone he smuggled inside a pack of baby wipes.

His videos show inmates crowded into tiny cells with filthy with hole-in-the -floor toilets, sleeping on mats side by side so they are lying shoulder to shoulder.

He says up to 130 men were sharing one cell - let out for only an hour a week.

He arrived in Thailand in April - hoping to set up a business and settle there.

But he was arrested in November, in Pattaya, and later charged with overstaying on his visa, he says.

And as a result was held in custody for two weeks before being deported, on December 5.

The man, who now works in marketing, said: "The conditions were absolutely disgusting."

"I was so shocked. It was unreal."

"The deportation centre was the worst. The only way I can describe it is hell."

"There was no ventilation and 130 of us in the room. We could only go out for an hour a week."

"At the deportation centre they'd bring in a big pot of food and you'd each get a tray to eat off. The trays were then washed in cold water on the bathroom floor - which was filthy."

"In all locations there were fire ants and cockroaches. The rubbish wasn't collected - it was just piled in the corner."

"There was a guy who sat in one corner selling tiny pot noodles - that was the only thing I'd eat."

The man said it was commonplace for people to overstay on Thai visas and he believed officials usually asked for a small fee to renew the documents.

But he was arrested after a disagreement with an ex, he says.

Police checked his passport and found he was a few days late renewing his visa, he said.

The police asked him to pay 50,000 Baht (£1,180) instead of 500 to release him straight away, and he couldn't pay it, he said.

He was taken to court the next day where he was asked to pay 2,000 Baht for the visa overstay and 500 for the cost of the night he'd been detained.

He was also banned from visiting Thailand for five years and sent to a deportation centre until his flight home had been arranged.

He was then detained until December 5, and deported.

He said: "When I was arrested they were very violent."

"Two police came up behind me in a public toilet and beat me."

"They chucked me in a flatbed of a truck and handcuffed me to the side."

"I was very dazed - I'm sure I had concussion."

"They didn't tell me anything. Luckily there were some Russian guys sharing my cell who spoke Thai so they told me what to expect."

"One of them lent me the money to pay my court fine straight away otherwise it would have been even worse for me."

Eight days were in a police cell in Pattaya - where eight inmates were crowded into a six-by-four foot cell.

He bribed guards to have a few people moved to another cell to allow more space, he said.

He also payed bribes to have food brought in, for cleaning products to get the bathroom more sanitary, and to send messages to his mum in the UK, he said.

He said: "The cell was tiny. We couldn't lie down properly and certainly not all at the same time."

"There was a pregnant girl from Laos who was really struggling. She was crying all the time with her head on the floor."

"It was horrible."

"There was another cell of the same size with 13 people in."

Eventually he was moved to Bangkok to the deportation centre, where he saw the most shocking conditions, he said.

130 inmates shared four hole-in-the-wall toilets which they cleaned with a bucket of cold water, her said.

And they washed by filling tiny bowls from a cold water bucket.

Once a week the detainees were taken to a room with an open, barred, roof to walk around for an hour, he said.

He was there for five days while his mum battled the British embassy to have him flown home, he said.

Eventually, after paying for the flight home plus 500 Baht per night for the five nights in the deportation centre, he was released to fly home.

He was able to take the footage because he smuggled in his phone in a pack of baby wipes, he said.

He said: "Once you're in there you have no contact with anyone and no way to get your money, so unless someone is fighting for you on the outside and knows you're there you have no hope."

"I'm very lucky I managed to get my phone in and that my mum was contacting the embassy: otherwise I'd still be there."

"The deportation centre was the worst thing I've seen in my life."

"I really want to put it all behind me but it's important for people to know what it's like: I want people to know what goes on over there."

"Lots of people let their visas run out and then pay a small fee to renew them, but don't do it, don't risk it at all."

"I don't want anyone else to become a victim of this."

"I'm never going back to Thailand."

"Tourism built and holds up their economy but they just want more. They imprison people then charge them but give them no means to access their money to pay, so they're basically stuck and it's a money maker for the authorities."