Irn-Bru brand owner AG Barr has reported a 4.3% increase in full-year profit before tax to £35m.

The soft drinks group also posted a 6.6% increase in turnover to £237.6m for the year ending 26 January.

It said core brands such as Irn-Bru and Rubican all grew, with energy drink brand Rockstar performing particularly strongly. Profit margins slipped as a result of rising input costs, particularly sugar.

AG Barr is currently working with the Competition Commission in the hope of gaining clearance for its merger with Britvic.

“We are now entering a period of significant workload associated with the Competition Commission enquiry, however the AG Barr board considers there to be a compelling rationale for clearance and that the benefits of the transaction remain significant for both shareholder groups,” said AG Barr CEO Roger White.

Britvic and AG Barr agreed terms of a merger to create a £1.5bn-turnover soft drinks company called Barr Britvic Soft Drinks in November.

White added AG Barr was also ploughing ahead with plans to ensure the success of the business as a standalone entity. Its new factory in Milton Keynes is on track to become operational in summer 2013, it said.