The UK Singles Chart is the official record chart in the United Kingdom. Until 1983, it was compiled weekly by the British Market Research Bureau (BMRB) on behalf of the British record industry with a two-week break each Christmas. The BMRB used motorcycle couriers to collect the sales figures taken up to the close of trade on Saturday. This data was compiled on Monday and given to the BBC on Tuesday to be announced on Johnnie Walker's afternoon show and later published in Music Week. On 4 January 1983, the chart was taken over by Gallup who expanded the chart from the Top 75 to the Top 100 and began the introduction of computerised tills which automated the data collection process. The chart was based entirely on sales of physical singles from retail outlets and announced on Tuesday until