The contract, which was put out to a competitive tender by the Department of Finance’s Central Procurement Directorate (CPD), is the first time the NI government has given the task of sorting and transporting of all of its mail to one firm. The value of the contract, which starts this month, was not disclosed.

Previously contracts have been awarded to local operations. Whistl is the only alternative national postal provider in the country.

Buckinghamshire-headquartered Whistl, formerly known as TNT Post UK, will sort and transport mail from all NI government and public sector bodies including health, education, finance and transport, to Royal Mail for delivery.

In order to compete for a contract of this size Whistl doubled the footprint of its Newtownabbey, Belfast site, operational since 2010, to 11,000sqm earlier this year and increased its capacity from 32 to 144 sorting bins. The expansion will enable the business to increase annual mail volumes from 20 million to 60 million items.

Under the terms of the deal Whistl has committed to boosting employment in the area and intends to recruit 10 new staff to fill new driver and operative positions.

Whistl chief executive Nick Wells, said: “Whistl is delighted that we can invest in new employment opportunities for some long-term unemployed people as well as apprenticeships following the award of this significant contract.

“We are delighted that we won the contract on our ability to provide a cost-effective quality service that will benefit the Northern Ireland tax-payer through lower postal costs but also to help get people back into the work place.”

Based in Marlow, £600m-turnover Whistl was formerly called TNT Post UK and operated as a subsidiary of PostNL since 2011. The company rebranded as Whistl in 2014 and was bought from the Dutch firm in an MBO the following year.