What was the title of ABBA`s first UK hit single?

Abba's first UK hit single was titled "Waterloo." The song was released in 1974 and quickly became a commercial success, catapulting the Swedish band to international fame. With its catchy pop sound and energetic performance, "Waterloo" won the Eurovision Song Contest for Abba, solidifying their status as prominent musicians and marking the beginning of their global domination in the music industry. The song's success paved the way for their subsequent chart-topping hits and cemented Abba's legacy as one of the most successful and influential bands in history.