Blair's deafening silence on why he won't oust Mugabe

The Prime Minister also sidestepped demands to explain why he went to war to remove Saddam Hussein, but had not considered similar action to oust the African tyrant.

Mr Blair was grilled about his policy on Zimbabwe after talks with South Africa's President Thabo Mbeki in Pretoria.

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Earlier in the week he had talked of the importance of intervention in other countries when necessary.

During his trip to Sierra Leone, where British troops helped end a civil war in 2000, he insisted: 'Intervention is not only right, it is the only thing that works.'

Under Mugabe's regime, tens of thousands of opponents have been murdered or tortured, white farmers have been forced from their land, millions of citizens are starving or have been made homeless and poverty is rife. At a press conference, Mr Blair was asked to explain the difference, when it came to intervention, between the regimes of Mugabe and Saddam, who British forces helped remove from power in Iraq in 2003.

Looking a little flustered, he declined to answer, saying if he were to do so it would 'quite likely turn into a PhD thesis on comparative regimes'.

He said: 'What is important is to improve the conditions for

the people of Zimbabwe and the obligation of Britain is to do everything we can to help.

'But I think people should know that at the end of the day the solution is an African solution. We will do whatever we can to support the changes necessary for a lot of the people in Zimbabwe, but that is something that will have to come from within Africa.

'I get attacks from both ways round on this issue.

'I get attacked for not singlehandedly changing events myself and I get attacked on the other side by people saying when Britain intervenes it is the least helpful thing in relation to this.'

Later, during the filming of a Question Time-style television programme, he was urged to take much stronger action to force Mugabe from power, but defended his approach.

He said: 'I am aware of the fact that me attacking Mugabe's regime does not do an awful lot to displace him.

'Sometimes the rhetoric that is used by elements of the Zimbabwe regime about the struggle for freedom, which was itself a noble struggle, is used to disguise a lot of things that would not be easy to reconcile with that noble struggle.'

But he said if African nations make efforts to bring about 80-year-old Mugabe's downfall, Britain is ready to offer ' assistance and help'.

President Mbeki says he is taking part in 'quiet diplomacy' with members of Zimbabwe's opposition Movement for Democratic Change.

Mr Blair believes it is ' essential' that Mugabe quits as leader before next year's elections in Zimbabwe, which have been rigged in the past.

Sources said it is impossible for the Premier to speak out loudly against Mugabe because the dictator would use the words to win support in Africa against 'interference by former colonial powers'.

It was the final day of Mr Blair's farewell tour of Africa.

He has discussed with African leaders pledges of aid, climate change, upcoming World Trade talks and the need to eradicate HIV and Aids.