The use of the flag at the web site constituted an insult and tarnished the country's image, the Thai Prime Minister's office permanent secretary Yongyuth Sarasombat said, according to the Bangkok Post.
The case has been forwarded to the Attorney General's office. The webmaster could face up to a year's imprisonment and a US$47 fine for violating the National Flag Act, and three years imprisonment and a US$95 fine under the Criminal Act.
The Bangkok Post added that some legal experts thought it unlikely that the woman would be extradited, as the British government would not take action over minor charges.
A police officer told the Age, an Australian daily, that the police had contacted their British counterparts to locate the woman, and that they were awaiting a report from the British side before taking further action.
Thailand has a thriving sex industry, with recent debate over possible legalisation of prostitution. The Thai government is trying to clean up its image as a sex tourism hotspot. Offences against Thai national symbols and the Thai monarchy are considered serious in Thailand.
In 2002, U.S. pop star Christina Aguilera's single "Dirrty" was banned in Thailand, Xinuhua, a Chinese news agency said. The music video featured Aguilera dancing next to a wall with Thai-language posters that said "Thailand's sex tourism" and "Young underage girls".
