
U is for... Underscore - Constant background music played at a low but audible volume for the purpose of heightening dramatic tension.
| Title | Genre |
| UK's Best Part-Time Band | Variety |
| Ulster Schools Quiz | Quiz, academic, regional (Northern Ireland) |
| The Ultimate Playboy | Reality |
| Ultimate Dealer | Lifestyle |
| Ultimate Goal | Football, recruitment |
| Ultimate Shopper | Reality |
| Ultimate Sports Day | Childrens, sports |
| Ultimate Traveller | Lifestyle |
| Ultimate Wedding Planner | Lifestyle, weddings |
| The Ultimate West Wing Challenge | Quiz, themed (The West Wing) |
| Ultra Quiz | Quiz, general knowledge |
| The Umpire Strikes Back | Comedy panel game (sports) |
| Un Cwestiwn | Children's general knowledge quiz (Wales) |
| Unanimous | Reality |
| Unbeatable | Quiz, general knowledge |
| Unbeatable Banzuke | Action and adventure |
| The Unbelievable Truth | Radio, comedy panel game |
| Unbreakable (1) | Stunts and dares, reality |
| Unbreakable (2) | Reality |
| Undeniable | Comedy panel game |
| Undercover Dads | Childrens |
| Undercover Lovers | Dating |
| The Underdog Show | Lifestyle, reality |
| Under Manning | Comedy panel game |
| Under Offer | Panel game |
| Under Pressure | Sports |
| Unearthed | Reality, Creative |
| The Unfair Quiz | Radio, comedy panel game |
| Unforgivable | Comedy panel game |
| University Challenge | Quiz, academic |
| UnsignedAct | Variety, reality |
| Unspeakable | Words, radio panel game |
| Unzipped | Stunts and dares |
| Up for the Cup | Variety |
| Upshot | Quiz, general knowledge |
| Upstaged | Variety |
| UTV Schools Choir of the Year | Variety, regional (Northern Ireland) |