ITV began broadcasting in 1955. Its first contractors were Associated-Rediffusion, broadcasting to London on weekdays and Associated Television (ATV London) as the London weekend contractor.

In February 1956 Associated Television (ATV Midlands) launches ITV in the Midlands and the following day the Midlands’ weekend contractor Associated British Corporation (ABC Midlands) broadcasts for the first time. In May 1956 Granada Television launches ITV in the north of England and two days later the north of England’s weekend contractor Associated British Corporation (ABC), broadcasts for the first time.

In August 1957 ITV starts broadcasting in central Scotland with Scottish Television as the franchise holder. In January 1958 Television Wales and the West (TWW) starts broadcasting to South Wales and the West of England. In August of the same year Southern Television launches.

In January 1959 Tyne Tees Television launches. In October 1959 Anglia Television launches and ITV launches in Northern Ireland when Ulster Television starts broadcasting.

In April 1961 Westward Television launches. In September 1961 Border Television and Grampian Television both launch.

In September 1962 Channel Television launches and the final part of the UK gets an ITV service when Wales (West and North) Television launches in West and North Wales as Teledu Cymru.

In January 1964 Wales (West and North) Television stops broadcasting after going bankrupt. It is replaced by TWW. However the Teledu Cymru on-air identity is retained.

In March 1968 TWW stops broadcasting five months before its contract was due to expire. The ITA provided an interim service called interim service until 20 May when the new contractor, Harlech Television, took over. In July 1968 Yorkshire Television launches following the decision to split the north region into two resulting in a new franchise for the Yorkshire area. Also in July, Thames Television replaces Associated-Rediffusion as the holder of the London weekday franchise although Redivision retains a 49% stake in the new company. London Weekend Television (LWT) replaces ATV as London’s weekend franchisee.

In 1968 ATV starts broadcasting to the Midlands seven days a week and Granada starts broadcasting across the north west seven days a week. In both cases ABC loses the right to broadcast. Also in 1968 the TV Times is launched as a national magazine to provide listings for ITV. In the same year a technician's strike forces ITV off the air for several weeks although management manage to launch a temporary ITV Emergency National Service with no regional variations.

In November 1969, ITV starts broadcasting in colour although it wasn't until 1976 that colour was available across the entire ITV network.

In 1972, ITV is able to launch an afternoon service. As part of this new service the first edition of Emmerdale Farm is broadcast and ITV's first lunchtime news programme, First Report is shown.

The 1974 franchise round sees no changes in contractors. However the Belmont transmitter in Lincolnshire switched from Anglia Television to Yorkshire Television and the Bilsdale UHF transmitter, based on the border between Yorkshire Television and Tyne Tees Television and much disputed over, was assigned to Tyne Tees Television.

In 1978 ITV's teletext service ORACLE launches.

In December 1980 The Independent Television Authority announces the new contractors to commence on 1 January 1982. The Midlands region will be split into two and dual regions will be created for Wales and the West and the South and South East. ATV is re-awarded its contract for the Midlands although there are several conditions including more regional content and increased production facilities in the Midlands. It is also told to rename itself and chooses the name Central Independent Television. Southern Television lost its licence for the South of England, in favour of Television South (TVS) and Westward Television also lost its licence for South West England and was replaced by Television South West (TSW). The Independent Broadcasting Authority also announces that TV-am has been awarded the contract to provide a national breakfast television service.

In January 1982 Central, TVS and TSW start broadcasting. Also the Bluebell Hill transmitter in Kent was transferred from Thames/LWT to TVS, to increase the size of TVS's new South East sub-region.

In 1987 many of the larger ITV companies start broadcasting into the night and in August Anglia and Thames/LWT become the first stations to begin 24-hour broadcasting.

In October 1991 The ITC announces the results of the franchise round. Following the Broadcasting Act 1990, the ITC had to conduct a franchise auction whereby contracts would be given to the highest bidder, subject to fulfilling a programming ‘quality threshold.’ TSW lost the South West of England franchise to Westcountry Television, Thames Television lost the London weekday franchise to Carlton Television, TVS lost the South of England franchise to Meridian Broadcasting, TV-am lost the national breakfast television franchise to Sunrise Television, which changed its name to GMTV before launch because of a dispute with British Sky Broadcasting over the name 'Sunrise', and ORACLE lost the National Teletext franchise to Teletext Ltd.

In June 1992 Yorkshire and Tyne Tees television merge, beginning a process that would see the consolidation of ITV over the next decade. In January 1993 GMTV, Carlton, Meridian and Westcountry start broadcasting. Also in 1993 Teletext launches as ITV’s new teletext service.

In 1994 Granada Television buys LWT, and Carlton Television takes over Central Independent Television. In 1996 Carlton Television buys Westcountry Television and increases its stake in Central Independent Television to 81%.

More consolidation takes place in 1997. Granada Television acquires Yorkshire-Tyne Tees Television, Scottish Media Group (SMG), which owned Scottish Television, acquires Grampian Television and United News and Media, the owner of Meridian Broadcasting and Anglia Television, purchased HTV.

In 2000 United News and Media sells its three stations - Meridian, HTV and Anglia - to Granada Television.

In January 2004 Carlton and Granada merge to create a single England and Wales ITV company called ITV plc.