Thailand’s ruling coalition was last night facing the most serious challenge of its short tenure, as thousands of protesters remained holed up in the Government House compound, after besieging several state buildings.

The People’s Alliance for Democracy (PAD), the royalist coalition that led the protests, described the agitation as a “final showdown” with an administration they see as little more than a proxy for Thaksin Shinawatra, the ousted prime minister. The PAD also led the massive protests preceding a September 2006 military coup against Mr Thaksin.