"I am returning to my political home as the Congress alone could take the country forward taking all the people together. From now on my energy would be channelised in that direction," 89-year-old Karunakaran said in Thiruvananthapuram at a convention of his supporters drawn from all parts of the state.

"I had differences with the Congress leadership. But now I realise it was a mistake on my part to have quit the Congress. I have no difficulty in admitting even standing on the top of Himalayas, that it was a mistake," he said.

Speaking on a podium with a tricolour board featuring Mahatma Gandhi, Jawaharlal Nehru, Indira Gandhi and Rajiv Gandhi, he said if the Congress became weak the country would get weakened.

On his son K Muraleedharan's refusal to toe his father's political line, Karunakaran said he was confident that the latter would also follow suit as no well-meaning person could think otherwise in the prevailing political circumstances.