UK Top 20 Week 42, 2021

This is an estimated (but likely accurate) UK Top 20 (might extend to 40) without the ACR or 3-single rules.

ACR was added in 2017 and basically means - if a song has charted for at least 10 weeks, and has declined in streams for three consecutive weeks, it is put onto ACR. This means its streams are halved, and count at the following ratios:

200 premium streams = 1 sale
1200 ad-funded streams = 1 sale

Songs older than 3 years old are automatically on ACR.
 

The 3-single rule only allows 3 singles from the same main artist to enter the chart. For example, if Dave had 4 songs on the chart, but was a feature on one of them, they would all enter. If he wasn't a feature but also wasn't the main artist on the song, the song would chart.