UK Train Operating Company.
Operates the following routes:
The Hunts Cross - Southport line is notoriously unreliable - if a train breaks down (and they do often), there's no way for other trains to pass it, and services in that direction are effectively cancelled until it's fixed.
Part of bus and rail group Arriva, and likely to be rebranded as such.
Source: UK Rail Info, www.railinfo.freeserve.co.uk - and personal experience