A £100 deposit bonus in the UK is a popular promotional offer provided by online casinos and betting sites to attract new players. When users make their first deposit, the site matches it with an additional £100 in bonus funds, allowing players to explore games and betting options with extra capital. This bonus often comes with specific wagering requirements, meaning players must bet a certain amount before withdrawing any winnings. It's essential to read the terms and conditions carefully to maximize the benefits of the offer while ensuring a fun and responsible gaming experience.