The suspect behind the leak of confidential memos from Britain's Washington ambassador, which sparked a major diplomatic rift with the United States, has been identified, the Sunday Times newspaper reported.

Last week, Britain's Mail on Sunday newspaper published memos from Kim Darroch in which he described Donald Trump's administration as "inept" and "dysfunctional," prompting an angry response from the U.S. president and causing the envoy to announce his resignation.

British officials have launched an inquiry to find the person responsible for the leak and counterterrorism police said on Friday they had launched a criminal investigation.