Britain said on Friday it would strongly support Zimbabwe's re-entry to the Commonwealth and praised President Emmerson Mnangagwa for impressive progress since Robert Mugabe was toppled in a military coup.
Zimbabwe left the organisation of 53 mostly former territories of the British Empire in 2003 after Mugabe, who had ruled Zimbabwe from its independence in 1980, was criticised over disputed elections and land seizures from white farmers.
"The UK would strongly support Zimbabwe's re-entry and a new Zimbabwe that is committed to political and economic reform that works for all its people," the Foreign Office said in a statement.
Mugabe cast himself as a liberation hero but opponents said he turned Zimbabwe into an economic basket case and international pariah. He was forced to step down in November during a coup and Mnangagwa is now president.
Foreign Secretary Boris Johnson, speaking on the sidelines of the Commonwealth Heads of Government Meeting (CHOGM), said July's election will be a bellwether for the direction of a new Zimbabwe.
"The Zimbabwe government must deliver the free and fair elections the people of Zimbabwe deserve and which it has promised," he said.
The West slapped sanctions on Mugabe and members of his inner circle, accusing them of rigging a series of votes - charges they denied.
Now Zimbabwe has said it will invite Western powers to monitor its national elections for the first time in more than 15 years.
"President Mnangagwa has been in power for 150 days and while Zimbabwe has made impressive progress, there is still much to do," Johnson said. "That's why Britain, the Commonwealth and the wider international community will do everything it can in supporting Zimbabwe on its path of reform."
"The UK stands ready in friendship to support a Zimbabwe that fully embraces the rule of law, human rights and economic reform," Johnson said.
The election will pit Mnangagwa against a clutch of opponents including 40-year-old Nelson Chamisa from the main opposition Movement for Democratic Change.
It will be the first time that Mugabe has not been on the ballot since independence from Britain in 1980.