SINGAPORE - Prime Minister Lee Hsien Loong has congratulated his British counterpart for emerging victorious in the general election which saw Mr Boris Johnson returning to power with a big majority.

"As you negotiate your future relations with the European Union and enhance relations with other partners, including in Southeast Asia, I hope that the United Kingdom will continue to be a strong advocate for free trade, multilateralism and a rules-based international order," Mr Lee wrote in a letter to Mr Johnson on Friday (Dec 13).

Underlining the robust relationship between the two countries, PM Lee said many initiatives, including in areas such as digital government, cyber security and green finance, have been developed since the launch of the Singapore-UK Partnership for the Future in January.

"We have a substantive agenda together, building on our longstanding ties in defence and security, trade and investments, and education, science and research," Mr Lee noted.

"I look forward to working with you to further strengthen our relationship in the coming years."

Results of Thursday's vote showed Mr Johnson's Conservative Party capturing 365 out of 650 parliamentary seats, its strongest showing since former British PM Margaret Thatcher's 1987 triumph.