'Defining moment for Zimbabweans' as Zanu-PF and opposition activists join forces to force Robert Mugabe to quit

Thousands of demonstrators are expected to rally in Harare on Saturday as an unprecedented alliance of Zanu-PF hardliners and opposition activists seek to force Robert Mugabe step aside as Zimbabwe's president.

The rally, which has been organised by the country's influential War Veterans association but endorsed by opposition parties and civil society groups, is intended to convince Mr Mugabe he has lost public support and lend an air of legitimacy to the defacto military coup that saw him placed under house arrest. The march comes as further details emerged of plans by Zanu-PF, the party Mr Mugabe has led for four decades, to impeach him if he refuses to resign voluntarily.

"The game is up," said Christopher Mutsvangwa, the head of the War Veteran's association, at a press conference in Harare. "It's done, it's finished... The generals have done a fantastic job.

"We want to restore our pride and tomorrow is the day... we can finish the job which the army started," he said.  

Mr Mutsvanga said that the march was for "all Zimbabweans" and that police and the military would not arrest demonstrators. For years Mr Mutsvanga's association of veterans of the war for independence from white rule was a bastion of Mr Mugabe's rule, playing a key role in the seizure of white-owned farms and intimidation of opposition groups.

The group has clashed with Mr Mugabe in recent months. In a twist unthinkable just a few weeks ago, they will be joined by opposition parties including the Movement for Democratic Change and pro-democracy civil society groups.

Evan Mawarire, a pastor who was jailed by Mr Mugabe for organising protests and strikes last year, called on his followers to set aside political differences to join the demonstration.

"We are joining hands across social groups, we are joining hands across political divides, and we are uniting for a new and fresh Zimbabwe," Mr Mawarire said in a live streamed address.

"This is a big and defining moment for Zimbabweans."

The demonstration is part of a two-pronged strategy to pressure Mr Mugabe to resign and lend credence in the eyes of the international community to the military's claim that it is managing a "transition" rather than an illegal coup.

Mr Mugabe, 93, has been under house arrest since and senior ministers allied to his wife, Grace, were arrested by the army on Tuesday night. The generals' goal is to prevent Mr Mugabe from handing power to his 53-year-old wife. They are believed to be hoping to install Emmerson Mnangagwa, a former security chief Mr Mugabe fired as vice president two weeks ago, as Mr Mugabe's successor.

General Constantino Chiwenga, the head of the armed forces and the presumed architect of the coup, spent much of Thursday locked in talks with Mr Mugabe over his departure. But Mr Mugabe refused to step down, exploiting the reluctance of the coup organisers to violate the Zimbabwean constitution, which they fear would torpedo any claim to legitimacy and expose them to punishing sanctions from the Southern African Development Community, the 16-member regional bloc.

"No one wants to follow this through into a full blown military coup. That's the hold up," said Nick Mangwana, the head of Zanu-PF's British branch.

"He's within his rights to say he's constitutionally elected, and he's not the kind of guy to just give up."

Zanu PF regional branches are believed to be preparing to remove Mr Mugabe as first secretary and president of the party, which would remove him as president of the country, as early as Sunday. Proceedings to impeach him in parliament would then follow from Tuesday. However, Mr Mangwana said they would seek to persuade Mr Mugabe he has lost before doing so.

"The first stage is to say 'look, you have lost the support of your party because the entire electoral college is asking you to go,'" he said.  

"The second stage is there will be a huge demonstration and they will say to him: 'did you see the millions of people on the streets? They are telling you to go. It is not the military doing this."

Under the constitution, the ruling party would appoint an interim president to finish Mr Mugabe's term, which ends in August next year.  It is widely assumed that the interim leader would be Mr Mnangagwa, who would then lead Zanu-PF into a general election next year. Mr Mnangagwa fled to South Africa after Mr Mugabe fired him but is believed to have returned to Zimbabwe the day after the coup. He has not been seen in public since returning.