The Prince of Wales’s personal touch ensured that the Christmas post for one town was truly Royal Mail.

Charles helped out in a delivery room putting letters and cards into their correct slots when he visited Royal Mail’s office in Cirencester, close to his Highgrove home in Gloucestershire.

Wearing his trademark double-breasted suit, while workers wore high visibility jackets, the prince said “It’s very difficult, isn’t it?” as he debated over which was the right slot for a piece of mail.

The heir to the throne was helping Mark Messer sort letters and Christmas cards for residents of the Chesterton Park area of Cirencester.

Mr Messer, a postman for 34 years, replied: “It’s something that comes with a knack and know-how.”

After a few minutes, Charles seemed to be getting the hang of it and asked Mr Messer, 57, from Fairford, Gloucestershire, about the joys and pitfalls of the job.

The 57-year-old sorts mail at the office for around two and a half hours before delivering it in Whelford, Gloucestershire, for about five and a half hours on a typical day.

“Do you get any problems with dogs?” the prince asked.

“Just occasionally – it’s always the small dogs,” the postman said. “Rottweilers or Alsatians are fine. Give me those any day of the week. But a terrier will take a bite out of your ankles. Jack Russells, terriers, are the worst.”

Staff at the Cirencester Royal Mail office do not serve Highgrove – a branch in Tetbury does – but they will process more than 300,000 items of mail this week. This figure is up 19% on the same week last year.

The office, which has been operating at the site since 2006, employs 70 full-time and part-time staff. Between them, they serve 51 delivery rounds made up of 21,669 delivery points.

The prince went to the delivery centre to pay tribute to Britain’s postmen and women delivering what is expected to be the biggest ever festive mailbag in the organisation’s history.

Coronavirus restrictions have helped revive the art of letter and card writing and led to a big rise in parcel deliveries throughout the pandemic and in the run-up to Christmas.

“Parcels have gone up by a third and parcels account for about 60% of our business,” said David Gold, Royal Mail’s public affairs director, who added that they were expecting a record year for card deliveries.

He said: “This year there is the sense that because people aren’t going to see others in person they are sending more cards. We are hearing that card shops are doing very good business.”

The prince toured the office and met many of the workforce, including Tim Lafford, 31, who was dressed as Father Christmas and Catherine Griffiths, 37, who wore an elf costume.

She was also holding a box of letters sent to Santa by children who get a reply from the great man via another department.

During the pandemic staff at the office have collected almost a tonne and a half of food for foodbanks and held other fundraising efforts for NHS charities and other organisations.

Charles, 72, who also inspected one of Royal Mail’s new environmentally-friendly delivery vans being piloted around the country during his tour of the building, congratulated them on their work keeping communities connected.

“You are marvellous how you keep it all going,” he told them. “Thank you for all your efforts and for bringing such joy to people.”

Before he left, he signed the visitor’s book and was given a framed collection of first class stamps depicting a stained glass window at St Andrew’s Church in Coln Rogers, Gloucestershire.

“Is it the 18th?” he asked before dating his signature. “I got it wrong yesterday. I thought it was the 18th yesterday.”