From the Wikipedia page [1]
London Weekend Television (LWT) was the ITV network franchise holder for Greater London and the Home Counties at weekends, broadcasting from Fridays at 5.15 pm (7:00 pm until 1982) to Monday mornings at 6:00 am. From 1968 until 1992, when LWT's weekday counterpart was Thames Television, there was an on-screen handover to and from LWT at each end of the weekend; from 1993 to 2002, when LWT's weekday counterpart was Carlton Television, the transfer occurred invisibly during a commercial break as Carlton and LWT shared studio and transmission facilities.
Like most ITV franchises, including Carlton's, the London weekend franchise is currently operated by ITV plc. As of 2014, the franchise is still separately licensed, but unlike many other franchises, it is no longer distinguished on air in any way. LWT is now managed with Carlton Television as a single entity (ITV London), and the legal name for LWT is now ITV London (Weekends). London Weekend Television Ltd is, along with most other regional companies owned by ITV plc, listed at Companies House as a "Dormant company".