AG Barr has forecast an increase of about 7% in full-year sales to £253m after reporting a 5% increase in its final quarter.

The maker of Irn-Bru said the increase in the quarter ending 26 January was “particularly pleasing” given that it was achieved against a double-digit rise a year ago.

The company said all its core brands performed well. It said its ‘Irn-Bru gets you through’ marketing campaign enjoyed a very positive consumer response and Rubicon and KA continued to build on strong prior-year performances.

“This should be viewed as a good performance in a challenging UK soft drinks market,” said Panmure analyst Damian McNeela.

The merger between AG Barr and Britvic is now expected to be effective from 26 February. The Office of Fair Trading is due to give its verdict on the deal on 13 February.