Prime Minister Gordon Brown said that Robert Mugabe's regime was "illegitimate" and had "blood on its hands".
He was speaking at the close of the three-day G8 Summit in Hokkaido, Japan, today.
There should be "no safe haven, no place to hide for the criminal cabal that make up the Mugabe regime", he said.
Earlier, the G8 leaders had criticised the Mugabe regime, calling for fresh sanctions against key members of his government.
They also recommended the appointment of a UN special envoy to the country. This is seen as a re-buff for South African President Thabo Mbeke. He has been leading Africa's negotiations with Zimbabwe.
It is thought that he told the G8 leaders on Monday that imposing sanctions against Zimbabwe could cause civil war.
The G8 leaders, meeting on the mountainous island of Hokkaido in Japan, expressed "grave concern about the situation in Zimbabwe". They "deplored" the latest round of elections and refused to recognise the Mugabe regime's legitimacy.
They called for a mediation process to install a new government in Zimbabwe.
A draft UN resolution citing travel bans and asset-freezing on key members of Mugabe's administration could go before the Security Council later this week.
Proposed by Britain and the US, it would additionally impose an arms embargo on Zimbabwe. This would include weapons, equipment and military vehicles.
Speaking at the G8 Summit, Prime Minister Gordon Brown said, "The G8 Summit has been overshadowed by the events in Zimbabwe.
"I hope that the whole international community will find it possible to condemn the illegitimate regime in Zimbabwe."
The G8's statement on the country reflected what Mr Brown called, "the unanimity of the whole international community, reflecting the outrage people feel about the violence, the intimidation and the illegitimate holding of power by the Mugabe government."
