Mugabe, who had led Zimbabwe since independence from Britain in 1980, resigned as president on Tuesday as parliament began impeachment proceedings after a military takeover.
Landers said following Mugabe's resignation, the people of Zimbabwe should be given space to determine their way forward, and that no solutions should be prescribed to them from other countries.
"From their past experience with the people of Zimbabwe, we have to allow the people of Zimbabwe to do what is expected of them without interfering", Landers added.
His resignation was announced by the speaker of Zimbabwe's parliament Jacob Mudenda. This should assist with the peaceful transition to a new leadership.
Many people here are envious of the rapid removal of Mugabe from office‚ when Zuma has survived multiple attempts to eject him‚ and the jubilation of the Zimbabweans.
"I'm so happy. I was suffering but now all of us we are celebrating".
"Working with our South African friends, with everybody in the region, that is what we are going to be encouraging, that is the choice we are going to encourage the Zimbabweans to make".
Speaking in the Foreign Office, Mr Johnson said: "Of course Robert Mugabe, 37 years ago not far away in Lancaster House, he played an important part in the birth of the independent nation of Zimbabwe".
The forum said Zimbabweans' victory gave hope to the people of the Democratic Republic of Congo, Swaziland, Zambia and Lesotho who are now struggling under the heavy yoke of oppression.
In a statement, Sadc Democracy Forum said Mugabe, together with his Zanu PF cronies, had been involved in widespread corruption, looting and mismanagement of State resources and other crimes which contributed to the country being a failed State.