BBC-1 and the big 4 ITV regions (London, Midlands, North West, Yorkshire) were due to go into colour with a big bang at the stroke of midnight on Saturday 15 November 1969. Of course, in London there were two ITV companies – Thames Television and London Weekend Television. Saturday fell under the management of London Weekend, so they went colour on schedule while Thames had to wait until Monday afternoon to open up properly in colour for the first time.
This led to a slight promotional problem for Thames. While the big campaign for the switch to colour was on-going, advertising the new colour service on its start date was advertising LWT, and the two companies did not get along for many reasons. So Thames let the national campaigns for the switch run, but mounted its own small campaign to remind people that Thames would also be in colour… but from Monday 17 November.
One promotional device was this sticker – in reality, about the size of a postage stamp – issued on sheets to staff for them to put on letterheads and envelopes. This also saved Thames the money of printing special stationery that would soon look out of date.