What was Michael Jackson's first UK number one?

One Day In Your Life, music written by Samm Brown III, Lyric by Renee Armand, Produced & Arranged by Samm Brown III. It was number one in the UK for 2 weeks in June 1981, succeeding Being With You by Smokey Robinson. It went on to become the 7th best-selling single of 1981 in the UK.