British Foreign Secretary James Cleverly speaks to members of the press in London on December 12, 2022. AFP
Cleverly said British diplomacy had sometimes been slow to capitalise on the shift in the geopolitical centre of gravity "eastwards and southwards".
But Brexit -- the UK's departure from the European Union -- provided opportunities to look beyond its nearest neighbours for new strategic partnerships.
Cleverly said the UK needed to have policy aims for up to 20 years, in areas from trade to climate change, even if there was no immediate visible dividend back home.
Countries such as India, Indonesia and Brazil, with much younger demographics than the UK's traditional allies that helped set up the post-World War II global institutions, will become increasingly influential, he said.
"I am determined that we will make investments of faith in the countries that will shape the world's future," he said.
"We can't just hang on to the comfort blanket perhaps of our pre-existing friendships and alliances," he added.
"We need to work, we need to graft, we need to make sure that we're having conversations with those countries that are also being wooed by other philosophies and we need to sell the benefits."
Since the UK left the EU, London has been pushing a policy of "Global Britain", particularly a "tilt" towards the Asia-Pacific region.
But excerpts of Cleverly's speech released in advance raised questions about whether he was advocating closer ties with some non-aligned countries that are more prepared to flout the international rules-based system in areas such as human rights.
Convincing future partners about upholding international law, respecting human rights and diversity needed to take place "over decades", he said, aiming for persuasion over lecturing.
Cleverly hit out at Russia for trying to take the world back to a time when "might was right" and neighbouring states were treated as "prey".
He noted China's rise as an economic superpower in the last 50 years yet voiced concern about its rapid military expansion and supposed "no strings attached" partnerships with developing countries.
But his overarching aims come as the UK backslides on one of its main "soft power" weapons by cutting international aid funding and by tightening immigration controls post-Brexit, despite an employment deficit in some sectors for overseas staff.
The ruling Conservative government, in power since 2010, is also well behind in opinion polls and facing defeat at the next general election due in the next two years.
"I'm willing to concede that I am unlikely to be foreign secretary in 25 years' time," he added, but said he wanted UK foreign policy to be more long-term.