British tourists were among seven arrested at an illegal gambling den in Thailand.

The gamblers, including Brits, Americans, an Australian, and a Russian, were detained at the underground casino just two blocks away from a police station in Thai 'Sin City' Pattaya on January 6.

Immigration officers and tourist police raided the building following reports of a gambling den disguised as a bar in the area.

Police Colonel Napatpong Kositsuriyamanee, superintendent of the Chonburi Immigration Office, said: ‘The operation was launched after we received a tip-off about a building operating a beer bar on the first floor.

‘We conducted an investigation and confirmed that its second floor was being used as a casino. We then coordinated with relevant local organisations to carry out the raid and arrest these foreign gamblers.'

The tourists, as well as five Thai natives working at the casino, were arrested and hauled to the police station. 

Police also seized a gambling table, chairs, several decks of cards, poker chips, equipment, 15 mobile phones, a radio, and 5,000 baht in cash.  

The casino operator, Phumipat, 28, claimed he rented the second floor and converted it into a casino catering to foreign gamblers.  

He said: 'The gamblers organised themselves through a group on the Line application. They held one or two casino games each week, and each session would last up to six hours. Though poker is considered a form of entertainment abroad, I admit that it is still illegal in Thailand.'

Most forms of gambling are illegal in Thailand under the country's Gambling Act of 1935.

Poker, and other games like slot machines and baccarat, fall under the law's 'List A' and are prohibited.

Organisers of List A games may be punished with detention between three months and three years, and a fine ranging from 500 to 5,000 baht.

While players may be either jailed for up to three years, fined up to 5,000 baht, or both.

Former fishing village Pattaya became popular with American troops on 'rest and relaxation' breaks in the 1960s when the U.S. military had bases in Thailand. In the ensuing years, the coastal resort spawned into a semi-barbarous sex-tourism hellscape.

Embarrassed officials have made progress in gentrifying the region with family tourism projects but a ravenous nightlife industry and corrupt police have hampered their efforts, with undesirables from all nations still attracted to the seedy city.