David Cameron is to urge the world to continue to give support to the emerging democracies of the Arab Spring as he addresses the United Nations General Assembly in New York.
And the Prime Minister will offer direct assistance on security and finance to Egypt in his first meeting with president Mohamed Mursi since his election in June.
Mr Cameron will say the UK stands ready to give Egypt expert advice on maintaining security in the sensitive Sinai area, where government troops have clashed with militants in recent weeks. And he will promise to cut through Brussels red tape which is delaying the repatriation to Egypt of assets valued at up to £100 million, stolen by the regime of deposed president Hosni Mubarak.
In his keynote speech to the General Assembly, Mr Cameron is expected to voice optimism about the prospects for Egypt and its neighbours in North Africa and the Middle East in the wake of the uprisings which forced Mubarak and other long-serving dictators from power.
While Britain sees little prospect of an imminent breakthrough on the continuing conflict in Syria, Mr Cameron is also expected to press world leaders gathered in New York to support humanitarian efforts to help those caught up in the violence.
A senior UK Government source said that Mr Cameron recognises the "concerns and worries" felt in Western capitals over the election of people with Islamist backgrounds to positions of power in Arab Spring states.
But the source said the Prime Minister believes the new governments emerging in the region should be judged by their actions, citing moves by Mr Mursi - who came to prominence as a member of the Muslim Brotherhood - to clamp down on Islamist militants in the Sinai.
Reining in radical activities is thought to be a key to calming Israeli concerns over security on its borders, as well as paving the way to the return of economically vital tourists to Red Sea resorts.
"Of course everyone has concerns and worries and interests. There will be all sorts of questions in people's minds," said the senior Government source. "You have got to judge people by what they do. He made an impressive start going after the militants in Sinai. That is quite an important move. The Arab Spring is working. Look at the reaction in Libya to the appalling events at the US consulate. There were 35,000 people on the streets saying this is not us and going after the militants."
Mr Cameron last night co-chaired the first meeting of a new high-level panel tasked by UN secretary general Ban Ki-moon with drawing up a new framework for global development after 2015. He reaffirmed Britain's commitment to increase its aid spending to the UN target of 0.7% of national income by 2013. And he urged other countries to live up to their promises to deliver funding to meet the Millennium Development Goals, which expire in 2015.