At an asylum appeal hearing in Newport, South Wales, Mr Justice David Archer said Machemedze was 'deeply involved in savage acts of extreme violence'.
The tribunal also heard that some of the tortures 'were too gruesome to recount'.
He added: 'Whatever crimes he has committed he cannot be returned to face the highly likely prospect of torture and execution without trial, the Sun reported.
The appeal hearing was brought by the Home Office and followed a judgment earlier this month which allowed the pair to stay in Britain indefinitely but did not grant asylum.
At the earlier hearing, Senior Immigration Judge Robert Martin said: 'It is true that Phillip Machemedze committed abhorrent acts and deserves no sympathy or favours.
'However, it is also true that we are bound by the European Convention on Human Rights and Articles 2 and 3 are absolute,' New Zimbabwe reported.
Kate Hoey, Labour MP and head of the Commons All Party Group on Zimbabwe, said: 'This is a shocking decision. Asylum is for people who are at risk from despots, not for people like him.'
How about that EU referendum, Cameron??
For the past several years, several Saturdays a month a group of Zimbabweans and concerned activists have held peaceful protests outside Zimbabwe's embassy in London. I have seen them out and chatted with them several times. With them they always have pictures of victims who have been tortured and killed by Mugabe's henchmen. These images are absolutely horrific and stomach churning. That one of the monsters who committed these acts is allowed to live, on my tax dollars, in the UK is yet another example of how pathetic this once great country has become.
Don't count on any outpouring of outrage.