A British ornithologist is facing up to two years in prison in Thailand for allegedly running illegal birdwatching tours.

Avian enthusiast Nicholas Upton, 53, from Dartford, Kent, had reportedly been leading holidaymakers on unauthorised tours across wildlife sites in the country's northern and central regions.

Tourism officials launched an investigation following a tip-off from angry local guides that a foreigner was conducting trips - a profession that is reserved for natives.

Investigations found that Nicholas had been running the illegal business by himself for 10 years - booking hotels, organising trips, driving, and guiding visitors who availed of his services through his website, thaibirding dot com.

Undercover officers captured him on video appearing nervous as he signed into a nature reserve for an overnight trip.

Tourist police claimed he had endangered his clients as navigating national park roads required expertise and a license.

Nicholas was detained in Bangkok on Thursday, the final day of a marathon trip across the country with 10 foreign tourists. Police said he could not produce the necessary work permits.

The ornithologist was taken to Lat Krabang district station for allegedly violating the Tour Business and Tour Guide Act by operating an unlicensed tour business. The offence is punishable by up to two years' imprisonment, a fine of up to 500,000 baht (11,906 GBP), or both.

He also faces charges of working in Thailand without a permit.

On his website, Nicholas claims he had a 'first class bachelor's degree in Wildlife and Countryside Conservation' and almost a decade of experience in leading bird tours through various Asian countries.

Jaturon Phakdeewanich, Director-General of the Department of Tourism, said: 'The Department of Tourism is strictly enforcing its policy against illegal tours and unlicensed guides, and we have taken consistent, serious action.

'I would like to thank the public for their cooperation in monitoring, reporting and providing information that led to this arrest.'

Despite having relatively liberal drug and sex laws, Thailand is notoriously strict with immigration and work-related offences.

Under Thailand's Foreign Employment Act, tourists are banned from working in dozens of occupations, including tour guiding, labour work, agriculture, and hairdressing. They are also prohibited from working in the country without a valid permit.

Violators may be fined 5,000 to 50,000 baht and may face deportation to their home country. They will also be banned from seeking a Thai work permit for two years.

While Thai employers may be fined between 10,000 and 100,000 baht per illegal employee.  Repeat violators face up to one year in jail, a steeper fine of 50,000 to 200,000 baht per illegal worker, and a three-year ban from hiring foreigners.

In another obscure case, Thai police raided a bridge club in 2016 after officers mistook it for a gambling den and detained 31 foreigners. They were later released.

While in September 2020, American tourist Wesley Barnes was arrested after a hotel owner filed a complaint against him for defamation over negative online reviews he posted, including on TripAdvisor and other platforms.

(1 GBP = 41.99 THB)