The company sent 28.7m leaflets to businesses and households across the UK - 1.2m pieces more than were distributed for the 2011 national census, according to the firm.

The project, which used 260 tonnes of paper, took five months of planning and three months of production. The last 82,000 boxes were dispatched at the end of May.

Print management firm Ink Print Management contracted The Website to produce the charity's donor recruitment campaign because of its fulfillment capacity, which mechanically encloses up to one million items per day.

To increase pallet capacity by 300, a dedicated racking system was installed at the facility, creating storage space for 1,500 pallets of envelopes throughout the production process.

The Website managing director Graham Glynn said: "It was a big job, but not a complex one – it was well within our capacity. We are one of the only printing and fulfilment companies in the UK to have the capacity to successfully complete such a large brief within a relatively short period."

The plant has recently combined its printing and fulfilment services at the same site, which has made it a popular choice with third sector organisations due to the reduced cost and smoother workflow.

The Leeds-based company, which is partnered with Glynn Print Finishers, has also recently completed a door drop campaign for the Red Cross. Pens were mechanically enclosed in 10m packs to deliver to 30 sites across the UK and Ireland.

Glynn added: "Our success in high volume projects is down to our ability to produce entire packs under one roof, which means we can forecast production rates and adjust resource as and when required."