Zimbabwe has "reached what may be a turning point" as the country waits to see what will happen following the apparent military takeover, Foreign Secretary Boris Johnson has said.

Mr Johnson said that "the path to a legitimate government now lies open" after the events of recent days, which have left Zimbabwe's military in control of the capital and President Robert Mugabe and his wife under house arrest.

It followed the sacking of Vice-President Emmerson Mnangagwa, who Mr Mugabe accused of plotting to take power. The move made his deeply unpopular wife Grace heir apparent and came after months of in-fighting in Mr Mugabe's ruling ZANU-PF party.

The military action was described as "a coup in all but name" by a former British ambassador to Zimbabwe.

It appears to have brought an end to 93-year-old Mr Mugabe's long reign. The military stressed it had not staged a takeover, but was instead starting a process to restore Zimbabwe's democracy.

British nationals in Harare are being advised by the Foreign and Commonwealth Office to stay in their homes or other accommodation "due to the uncertain political situation".

South African president Jacob Zuma said he has spoken to Mr Mugabe - who has been in power for 37 years - and stressed he is "fine" but confined to his home.

Zimbabwe's army said it also has first lady Grace Mugabe in custody and is securing government offices.

Writing in the Telegraph, Mr Johnson said that Mr Mugabe had "tarnished" the jewel that is Zimbabwe.

He wrote: "Today, in one of Africa's most fertile countries, many are close to starvation; the image that people in Britain have of Zimbabwe is not of the Victoria Falls or spectacular wildlife, but stolen farms and the bandaged victims of the regime's brutality.

"And now this disturbing story of plunder and misrule has reached what may be a turning point.

"All that we have ever wanted is for Zimbabweans to be masters of their own fate, as expressed through free elections.

"The path to a legitimate government now lies open. I hope that Zimbabwean politicians will take this opportunity, remembering that their country has so many strengths that even Mugabe has failed to tarnish it irreparably."

Speaking at Prime Minister's Questions on Wednesday, Prime Minister Theresa May called for an avoidance of violence.

She said: "We have all seen what has been taking place in Harare. We are monitoring those developments very carefully, the situation is still fluid, and we would urge restraint on all sides because we want to see and we would call for an avoidance of violence."

Meanwhile, Mark Canning, who served as British ambassador to Zimbabwe between 2009 and 2011, said that "there will be relief in many quarters at the end of the Mugabe era".

Describing it as "a coup in all but name", Mr Canning said that the action taken by the military was part of a power-struggle about presidential succession - after Mr Mugabe fired his deputy - and likely successor - Emmerson Mnangagwa last week.

"There will equally be hope that Mr Mnangagwa, who is viewed by many, including in the opposition, as a more pragmatic and business-friendly figure, can arrest Zimbabwe's downward spiral," he said.

Mr Canning added: "Zimbabwe has all the ingredients to claw its way back to the prosperity which its long-suffering citizens deserve - but only if Mr Mugabe's successor has the courage to abandon the disastrous policies of the past."