Somchai, also lawyer for social critic Sulak Sivaraksa, who was arrested on a lese-majesty charge on Thursday evening, said both pro- and anti-government groups were now playing with fire by calling for a crackdown on any speech or view even mildly critical of the monarchy.

"Some Democrat Party MPs are also calling for an amendment of the law to impose harsher punishment on those expressing critical views on the Internet, and that is problematic because in our age it's impossible to suppress communication," Somchai said.

"Both [pro- and anti-government groups] are also doing the same [by calling for a crackdown], and this will tarnish the monarchy. It's not good for the monarchy and will lead to a greater rift in society."

Somchai said that what Sulak had said in a public speech last December in Khon Kaen was very mild. Somchai also said the military had had a role in this by raising ultra-royalist fervour in recent weeks and this might explain why Sulak had been arrested.

Sulak was later given bail and flew to London last night for a pre-arranged engagement; he will return to Bangkok in November to fight the charge.

He told The Nation last night that he was "absolutely" innocent but "tired" and added that his trip had nothing to do with the case.

The arrest on Thursday took place amidst fear that many websites would soon be blocked, community radio shut down and academics writing critically about the monarchy arrested.