What was the title of Rihanna's first UK No. 1 single?

"Umbrella" is a song by Barbadian singer Rihanna from her third studio album "Good Girl Gone Bad" (2007). It features American rapper Jay-Z, who co-wrote the song with its producers Tricky Stewart and Kuk Harrell, with additional writing from The-Dream. The song was originally written with Britney Spears in mind, but her label rejected it. "Umbrella" is a pop, hip hop and R&B song with rock elements, referring to a romantic and platonic relationship and the strength of that relationship.

"Umbrella" was a commercial success, topping the charts in Australia, Canada, Germany, Spain, the Republic of Ireland, Sweden, Switzerland, the United Kingdom, and the United States. In the United Kingdom, where the song's chart performance coincided with the prolonged rain and flooding, it was one of the most played songs on radio in the 2000s decade.

Robyn Rihanna Fenty (born February 20, 1988) is a Barbadian singer, actress, fashion designer, and businesswoman. Born in Saint Michael and raised in Bridgetown, Barbados, Rihanna was discovered by American record producer Evan Rogers who invited her to the United States to record demo tapes. After signing with Def Jam in 2005, she soon gained recognition with the release of her first two studio albums, "Music of the Sun" (2005) and "A Girl Like Me" (2006), both of which were influenced by Caribbean music and peaked within the top ten of the US Billboard 200 chart.