Hundreds of riot police took up posts around Hong Kong's legislature overnight, as protests were expected on Wednesday over a bill criminalising disrespect of China's national anthem and against plans by Beijing to impose national security laws. The proposed new national security laws have triggered the first big street unrest in Hong Kong since last year, when violent protests posed Hong Kong's biggest crisis since the return of Chinese rule in 1997 from Britain. Activists say the security laws could bring an end to the autonomy of China's freest city, now guaranteed under a policy known as "one country, two systems".