Whistl has said it has strengthened its letter collection and sorting division with a series of contract wins that have boosted its downstream access (DSA) volumes.

Its biggest win comes in the form of Hotter Shoes, of which it is set to deliver 21 million items a year. It has also agreed mail delivery contracts with Serco and Griffin Media.

The company said that the recent client wins would see it handle over 3.75 billion items of mail this year.

Whistl, formerly TNT Post, has also revealed it has won DSA contracts with Royal Liverpool NHS; direct marketing firms Meridian Delta and Kingsline; online print company Vista Print; financial services specialists Admin RE; and outsourcer Mittie.

CEO Nick Wells said: “Our continued investment in core business divisions DSA and international, door drop media, packets and parcels and logistics are enabling us to broaden our client base and I look forward to announcing new client wins in the coming months.”

Last month Whistl confirmed that it would be ending its final mile delivery service after potential investment partner LDC, a branch of Lloyds Banking Group, decided against funding the company’s expansion plans.