The Foreign Secretary, Robin Cook, emerged empty-handed after eight hours of talks with three Zimbabwean cabinet ministers. The collapse appeared to end all dialogue at ministerial level between Britain and Zimbabwe, leaving President Robert Mugabe a free hand in the run-up to the promised elections, due next month.
Last night Mr Cook said: "I have refused to make any further progress until the essential next step is taken and that is for the occupations to come to an end."
Continuing his defiance of international opinion, Mr Mugabe tightened his grip on power by resurrecting legislation which was originally intended to suppress black political action in Rhodesia. The provision would allow police to restrict the movement of party activists and ban public gatherings that threaten law and order.
The meeting failed even to agree on a common statement. It had been convened to find a solution to the increasingly bloody takeovers of white farms. Mr Cook blamed the Zimbabwean delegation for intransigence in refusing to give a commitment to end violence.
But the Zimbabwean delegation claimed Britain was at fault in reneging on previous promises to fund land reform. A Foreign Office source described the exchanges as "frank, sometimes very frank".
The meeting, which began in the morning, had been scheduled to end at 4pm. It ran into the evening as the two sides found difficulty in agreeing a common position.
The Foreign Office source said the talks went round in circles, coming back each time to Mr Cook's call for an end to the violence.
In Harare the police commissioner, Augustine Chihuri, whose forces have been severely criticised for their failure to intervene, said that the implementation of the three sections of the Law and Order Maintenance Act was intended to halt the violence.
"In short, it is illegal to ferry supporters to meetings, public gatherings or processions unless such events are being officiated by presidents of political parties," he said.
But opposition parties said the move represented yet another attempt by the ruling Zanu-PF party to suppress opposition and claimed it would effectively outlaw all independent political activity.
All attention now focuses on the pressure that can be brought to bear on Mr Mugabe from his African neighbours. Last night the former South African president Nelson Mandela said everything was being done behind the scenes to persuade President Mugabe to "cool things down".
"The people of Zimbabwe are justified in expecting Britain to honour her pledge to finance the redistribution of land," he said, "though that does not justify their methods in taking the land. If Zimbabwe collapses we must handle the aftermath: thousands of immigrants will flow into South Africa where unemployment is already high.
"There is no danger of the violence spreading to South Africa, although the land here is largely in white hands. It will never occur in South Africa. There have been killings of white farmers, but that has mainly been the result of rough way farmers have treated black workers."
Mr Cook offered the Zimbabwean delegation a £36m economic aid package, some of it to go towards land reform, including compensation for white farmers. But, according to Foreign Office sources, the Zimbabwean delegation wanted the money without conditions attached. Mr Cook insisted that an end to violence was his bottom line.
As the day dragged on, the Foreign Office expressed frustration that the Zimbabwean delegation could not even agree to principles which it had signed up to at a conference on land reform two years ago. The Zimbabwean delegation retorted that Britain had reneged on that 1998 agreement.
The Foreign Office began to play down expectations, insisting there had never been any chance of a solution in London and that in the end the problem would have to be resolved in Harare.
The signs had been ominous before the meeting when Mr Cook appeared to lay the ground for shifting the blame for failure onto Zimbabwe.
At the same time, the Zimbabweans claimed that Britain was behaving like a colonial power and should not be interfering in internal politics.
Last month, it was hailed as a breakthrough when Mr Mugabe agreed to send a delegation after meeting Mr Cook at European Union-African summit in Cairo.
A Foreign Office source said: "Robin Cook said we were prepared to help on the 1998 agreement but only on the basis of the violence being ended."
The focus will now shift to a meeting of Commonwealth ministers in London on Tuesday.