Tullow Oil can proceed with the $1.5bn acquisition of a 50% stake in two big oil fields in Uganda from Heritage Oil after the government gave approval after months of wrangling.Tullow exercised its first refusal rights over blocks 1 and 3A in the Albert Basin in Uganda after Heritage agreed to sell the stakes to Eni of Italy.But the Ugandan government originally blocked the sale to Tullow fearing it would give too much control to the Irish group. There was also disagreement with Heritage over the amount of capital gains tax payable on the sale.With the issues now resolved, Tullow will bring in China National Offshore Oil Corporation and Total to develop the Albert Basin fields. It will also pay tax as part of the agreement."All the due diligence on Total and CNOOC has already been done by the government, so we can move immediately on the agreement," said Ian Springett, Tullow's finance director.