Whistl

Whistl (formerly TNT Post UK) is a postal delivery company based in Marlow, Buckinghamshire, England. The company primarily competes (and in some instances partners) with UK Mail, UPS, Parcelforce, DHL, Evri, Royal Mail and Yodel. According to the company, it processes about 25% of the mail in the United Kingdom, amounting to over 3.7 billion items per year in 2015.