Short answers, pulled from the story.
The first UK Albums Chart appeared on the 22nd of July 1956 with Frank Sinatra's Songs for Swingin' Lovers! at number one. No single official list existed to track album sales across the country before that date.
The system takes the 12 most streamed tracks from any given album and divides the total stream count by 1000 before adding it to pure sales numbers. The top two songs receive down-weighting to match the average performance of the remaining ten tracks.
ABBA's Gold: Greatest Hits became the first album to spend over 1000 weeks on the chart in July 2021. This total excludes the 40th Anniversary Edition released in 2014 or missing data before February 1994.
Neil Reid holds the record as the youngest artist to top the chart when his debut album reached number one in 1972 at just 12 years old. Billie Eilish became the youngest female artist to reach the summit at 17 with When We All Fall Asleep, Where Do We Go?.
In February 2015, the organization announced a major shift to include audio streaming data due to falling physical sales figures. On the 1st of March 2015, Sam Smith's In the Lonely Hour topped the new streaming-incorporated list.