The Colour Strike was a period of industrial action by technicians at all ITV companies which ran from 13 November 1970 to 8 February 1971 (although some shows made during this period in black-and-white were having their first transmission as late as December 1971) who, due to a pay dispute with their management, refused to work with colour television equipment.

At that time, ITV had recently switched to colour transmissions, requiring the individual companies to invest heavily in new equipment. Early colour television studio cameras consisted of four tubes to relay the picture: three were receptive to colour (red, green and blue – the chrominance signal) with the fourth providing a high-resolution monochrome image (the luminance signal). The final colour picture was created by combining the chrominance and luminance signals, but the technicians simply switched off the colour tubes whilst this dispute took place.^[1]

This meant that even though colour equipment was available, all shows were recorded and broadcast in black-and-white,^[2][3] thus denying the ITV companies the ability to sell airtime at the higher value that colour transmissions dictated.^{[citation needed]}

In some film sequences for location shots in these programmes (shot in colour), the colour signal from the telecine machine had to be switched off in the vision mixing desk before being recorded to tape, but this was partly unsuccessful, leading to some film sequences being recorded with an odd array of pale colours (as for items where the colour is a mix of two primary colours, only one primary colour would show). This is prominent in the second series of Hadleigh, for example.^{[citation needed]}

The first Coronation Street episode to be broadcast in colour was transmitted on 3 November 1969, but due to the strike, some 1970–71 episodes, including the one featuring Valerie Barlow's electrocution, were recorded in black-and-white. The last black-and-white edition was shown on 10 February 1971, although the episodes transmitted between 22 and 24 February 1971 contained black-and-white film inserts.^{[citation needed]}

All of ITV's programmes were broadcast in black-and-white throughout this period, including scheduled repeats and regional programmes. During this time, ATV showed a modified version of its regular caption slide An ATV Colour Production at the end of its shows, which had the word 'colour' blanked out, with Granada's regular caption slide also omitting the words 'Colour Production' to reflect this fact too.^{[citation needed]}

The strike was called off on 2 February 1971 with all colour production and transmissions resuming on 8 February.^{[citation needed]}

Four ITV regions were still broadcasting exclusively in black-and-white prior to the start of the Colour Strike and would not commence colour broadcasts until the following dates: Westward Television (22 May 1971), Border Television (1 September 1971), Grampian Television (30 September 1971) and Channel Television (26 July 1976).^{[citation needed]}

There was also a short dispute two years later in early 1973; this affected both BBC channels as well as ITV.^{[citation needed]}

• 1968 ITV strike
• 1979 ITV strike