Whistl UK is a leading UK delivery management company (formerly TNT Post UK) specialising in mail, parcels, fulfilment, and contact centre services. Headquartered in Marlow, Whistl coordinates domestic and international shipments through multi‑carrier networks and downstream access to Royal Mail. The business rebranded to Whistl in 2014 following its TNT Post era and continues to support retailers and brands with scalable logistics solutions.