Britain's vote to leave the European Union is "a turning point", said Prime Minister Lee Hsien Loong, as he wished the country well amid the uncertainty that lies ahead .

The referendum result - 51.9 per cent of about 33 million voters favoured leaving the union - reflects anxiety over immigration, resentment at having to accommodate European partners, and a desire to assert British identity and sovereignty, he said.

Other developed countries also face similar challenges as Britain, he noted. "We all live in a globalised, interdependent world. The desire to disengage, to be less constrained by one's partners, to be free to do things entirely as one chooses, is entirely understandable," he said in a Facebook post yesterday.

But the reality for many countries is that "disengaging and turning inwards will likely lead to less security, less prosperity, and a dimmer future".

As for what lies ahead, Mr Lee said the next few years will be uncertain for Britain and Europe.

"Leaving the EU is as complicated as joining it. What new arrangements will be made? Will this hurt investor confidence more broadly, and the global economy? How will Britain's leaving affect the rest of the EU? How will this affect us, living in Asia but part of the same globalised world?It is too early to tell, but we need to watch developments carefully. Nobody can foresee all the consequences of the Brexit," he said.

He extended good wishes to Britain and its Prime Minister David Cameron, who has since resigned. Mr Cameron, Mr Lee said, has been a good friend of Singapore. Singapore will continue to cultivate its ties with Britain, a longstanding friend and partner, he added.

"We hope in time the uncertainty will diminish, and we will make the best of the new reality."