By Alastair Leithead
BBC News, Bangkok
**Thousands of demonstrators are gathering in Bangkok to mark the third anniversary of the coup which ousted then Prime Minister Thaksin Shinawatra.**His supporters, who as a group wear the colour red, are mostly from the poor north and north-east of Thailand.
They are demanding a stronger voice in the way the country is run.
Their last protest, in April, ended in clashes. Security is tight in the Thai capital, with large numbers of police and military personnel deployed.
Colour politics
Mr Thaksin is now in self-imposed exile after being convicted on conflict of interest charges.
Tens of thousands of his supporters are expected to join the rally, in the centre of the city.
Their demonstration is about more than just marking the anniversary of the bloodless coup that forced him from office.
But he is taking advantage of deep divisions in Thai society between the powerful upper and middle class elite, and the poor, more rural Thais originally from the north and the north-east who make up the core of the red shirt movement and his support base.
The last time they took to the streets in large numbers was in April when the protests turned violent - buses were burned, streets blocked and the army sent in to end the demonstration.
The leaders of the red shirt movement - the United Front for Democracy Against Dictatorship - say they will ensure the protest does not turn violent.
But current Prime Minister Abhisit Vejjajiva is taking no chances and has given the military special powers under an Internal Security Act.
In the complex colour-orientated world of Thai mass-movement politics, the rival People’s Alliance for Democracy - identified by their yellow shirts and who were responsible for closing down Bangkok’s airports last year - are also planning a demonstration at the same time.
They will gather on the border with Cambodia near a controversial temple complex, the ownership of which has been a long-running source of tension between the two countries.