The former army commander, Sarath Fonseka said it was a mistake to field Maithripala Sirisena, the current president, as the common candidate in 2015.
"I told Prime Minister Ranil Wickremesinghe to contest the last presidential election but the party supported a common candidate instead. This was a blunder," Mr Fonseka told a May Day rally, the Daily Mirror reported.
Mr Fonseka, who sough the law and order portfolio, was made the Sustainable Development, Wildlife and Regional Development Minister.
“We have miserably failed in the last three years to fulfill the pledges given at two elections in 2015," Mr Fonseka told reporters.
"The people in 2015 voted for President Sirisena in January and to the UNP in August mainly to expose murderers, financial crimes, embezzlements and other misdeeds committed under Mahinda Rajapaksa regime and bring members of the Rajapaks family before the law and punish them. This did not happen as expected. The President should be held responsible for not taking action against the Rajapaksas. People voted en-mass against the government at the LG polls not because they had a special affection to the SLPP but because they had been disappointed over the government’s failure. Both the leaders should be held responsible for these failures,” Mr Fonseka added.