Department of Special Investigation and immigration police arrested 80-year-old Norman Lunt in Pattaya on Wednesday for extradition to face charges of rape and molestation in the UK.
DSI director-general Paisith Wongmuang said they were acting on a request from the UK's National Crime Agency. Mr Lunt faces 11 counts of molestation and serious molestation, and five counts of rape in the UK, he said.
The alleged victims were two daughters of people close to the suspect. They had allegedly been abused for about five years before Mr Lunt came to Thailand, Pol Col Paisith said.
The Criminal Court issued a warrant for his arrest on July 23 to facilitate his extradition.
The suspect was detained at house 128/43 in tambon Nong Prue of Bang Lamung district, Chon Buri. He was handed over to public prosecutors for extradition proceedings.