Express Dairies has warned that the delay of its £155m merger with Danish dairy group Arla due to its referral to competition watchdogs “would restrain profitability for the next few months”.

The Competition Commission will deliver its report on the proposed merger to create Arla Foods by September 24.

Express chairman Sir David Naish told the company's annual general meeting that trading so far had been in line with expectations “despite what remains a challenging market background”.