I find that if you want to know TV ratings, it's pretty easy to find ones for US TV shows with the Neilson Top 20 available all over the place but no one seems to publish the UK Top 20 so I'm going to start, these are official numbers from BARB for the week before last (week ending 27th August):

1. Coronation Street [ITV1] - 10.35m
2. EastEnders [BBC1] - 9.11m
3. Emmerdale [ITV1] - 8.05m
4. The X Factor [ITV1] - 7.36m
5. The National Lottery - In It to Win It [BBC1] - 7.09m
6. Casualty [BBC1] - 6.90m
7. Holby City [BBC1] - 6.10m
8. Silent Witness [BBC1] - 5.98m
9. Ten O'Clock News [BBC1] - 5.87m
10. BBC News [BBC1] - 5.73m
11. How Do You Solve a Problem Like Maria [BBC1] - 5.67m
12. Murphy's Law [BBC1] - 5.47m
13. The Bill [ITV1] - 5.26m
14. Where the Heart Is [ITV1] - 5.21m
15. Bad Girls [ITV1] - 5.00m
16. Sorted [BBC1] - 4.84m
17. The Chase [BBC1] - 4.34m
18. Crimewatch Solved [BBC1] - 4.28m
19. Edinburgh Military Tattoo [BBC1] - 4.28m
20. Jane Hall [ITV1] - 3.99m

One episode (highest rated) for each series only. Comprised from official BARB ratings for all national terrestrial TV channels: BBC1, BBC2, ITV1, Channel 4 and Five