Royal Mail has revealed a sharp fall in letter mailing during the busy festive season, blaming business worries over Brexit hitting marketing post.

The group said the number of addressed letters handled was down 6% in the nine months to December 25, against a 4% fall reported at the half-year stage, with letter revenues 5% lower for the first three quarters of its financial year.

Royal Mail said: “We are seeing the impact of overall business uncertainty in the UK on letter volumes, in particular advertising and business letters.” The group signalled an impact from Brexit fears on its letters arm in its half-year results in November, when revenues from advertising mail slumped 8%, and it said this trend had remained “broadly similar” in the third quarter.

This offset a stronger performance from its parcels business, which notched up a 3% rise in revenues over the nine months to Christmas Day, with the number of parcels delivered up 2%.

Total revenues across its UK parcels and letters division were still 2% lower but its European parcels business, General Logistics Systems, saw a strong festive quarter, pushing revenues 9% higher for the nine months and helping group-wide revenues hold firm on a year earlier.

Chief executive Moya Greene said: “Our postmen and women delivered a great service at Christmas, even better than last year, with 138m parcels handled in December alone. Our comprehensive planning, which started much earlier this year, enabled us to deliver this service for our customers right across the UK.”

Royal Mail said the third quarter comparison for letter mailings was hit particularly hard as it was up against an “unusually strong” Christmas a year earlier.

It added: “Letters performance in the prior period benefited from the one-off return of direct delivery volumes and a good performance over the peak period.”

Royal Mail’s Parcelforce Worldwide business suffered a tough Christmas, with parcel numbers down by 1% amid an “increasingly competitive” market”, but the group saw good growth in Royal Mail account parcels.