At the same time, 24% of respondents supported Starmer, while another 12% could not make an assessment, the report said on Tuesday.
The poll was conducted on January 13 and surveyed 1,698 people.
In a separate poll conducted from January 11-13, 62% of Britons said they disapproved of the government’s record to date, with only 17% claiming the opposite.
The Labour Party won 412 seats in the July 4 election, securing an absolute majority in parliament and ousting the Conservative government. The next day, Starmer was officially appointed as the UK's 58th prime minister.