I found an interesting list of the most downloaded mobile games in the UK.
Top 10 mobile games downloaded in the UK in July:

1. Tetris - EA Mobile / Blue Lava Wireless
2. Sonic the Hedgehog: Part One - Sega/Glu Mobile
3. Tiger Woods PGA Tour 06 - EA Sports / EA Canada
4. Worms - THQ / Kiloo
5. My Dog - I-play / I-play
6. Street Fighter II - Capcom / Capcom Mobile
7. The Fast and The Furious: Tokyo - I-play / I-play
8. The Sims 2 - EA Mobile / Ideaworks3D
9. Ms Pac-Man - Namco Mobile / Namco Networks
10. Blockbusters - Player X / Qbranch Wireless

source: http://www.moconews.net/uk-top-10-mobile-games-july.html
Top 10 mobile games downloaded in the UK in June:

1. Tetris - EA
2. Worms - THQ
3. Sonic The Hedgehog - Sega/Glu Mobile
4. FIFA World Cup Germany - EA
5. The Sims 2 - EA
6. Who Wants to be a Millionaire 2nd Ed - Glu Mobile
7. Championship Manager 2006 - Eidos
8. The Fast and the Furious: Tokyo Drift - I-play
9. Block Breaker Deluxe - Gameloft
10. Monopoly - Glu Mobile

source: http://www.moconews.net/uk-top-10-mobile-games-june.html