By Charles Haviland BBC News, Colombo

	Gen Fonseka says he wishes to end "one family poltics"

General Sarath Fonseka said he was entering politics with reluctance but that he could not leave the country, “in the hands of a tin-pot dictator”.

With this announcement, the soldier-turned-politician also denounced the government, above all President Rajapaksa and his three powerful brothers.

Sarath Fonseka said he would win the presidency and would abolish the executive presidential system which he said had been abused.

'One family' politics

Such a move, though, would require his backers securing a two-thirds majority in separate parliamentary elections.

General Fonseka dwelt on the war victory, saying this should not be the entitlement of “one family”.

'War crimes'  Anybody who can provide that type of reliable information, there’s no question why we should not do that investigation. We have never tried to cover up any indisicipline or illegal activity in the army during the war Gen Fonseka

In a reference to the Tamil minority, he said the victory was not scored against any one community. Similar remarks were made by the president when the war ended.

But the general also left open the possibility that he might be open to any alleged war crimes by the army being investigated.

"Anybody who can provide that type of reliable information, there’s no question why we should not do that investigation. We have never tried to cover up any indisicipline or illegal activity in the army during the war," he said.

The general accused the government of doing too little to ensure the welfare of Tamils displaced by the war.

He has a reputation as a hardline Sinhalese nationalist and many in the international community have criticised the manner in which he, the armed forces and the government won the war, saying there were too many civilian casualties.

Many of the differences between the general and the president seem to be based on personality.

But the mixed coalition of opposition parties is throwing its weight behind General Fonseka, sensing it can’t find an equally strong candidate within its own ranks.