Britain and France were to strike a deal on civil nuclear energy and discuss closer defence ties at a summit on Friday between Prime Minister David Cameron and President Nicolas Sarkozy in Paris.
The diplomatic stand-offs with Syria and Iran, in which London and Paris have been close allies on the UN Security Council, were also on the agenda for the lunchtime session at the Elysee Palace.
France and Britain have often clashed recently over economic policy in the eurozone, an area in which Paris is much closer to Berlin, but they are close partners in defence and now plan to share nuclear expertise.
Germany has decided to phase out nuclear power, but France still uses it to generate around three-quarters of its power and is keen to seize the market for the world's next generation of more powerful reactor technology.
"At our last summit, we signed a historic partnership on defence. Today, we will match that ambition on nuclear energy," Cameron said, in remarks released by Downing Street before he left London for Friday's talks in Paris.
"As two great civil nuclear nations, we will combine our expertise to strengthen industrial partnership, improve nuclear safety and create jobs at home. The deals signed today will create more than 1,500 jobs in the UK."
French nuclear giant Areva is pioneering development of the modern EPR reactor, but Cameron said that thanks to the agreement, British firms would make "the vast majority of the content of our new nuclear plants".
Downing Street said the British engineering firm Rolls-Royce will secure a £400 million (481 million euro, $632 million) share in the work to build Britain's first EPR at Hinkley Point in southern England.
Other British firms will sign deals worth a total of £115 million with France's state-owned energy giant EDF as part of the Hinkley project.
Renewed safety fears in the wake of last year's Fukushima nuclear disaster in Japan contributed to German Chancellor Angela Merkel's decision that the EU's biggest economy would begin to phase out nuclear power by 2022.
But France remains committed to the technology, and Sarkozy has attacked an opposition plan to gradually reduce the role of nuclear power.
Both Downing Street and the Elysee Palace said Friday's summit would also tackle the crisis in Syria and the broader question of Franco-British defence cooperation following their close collaboration in the Libyan campaign.
"One year on from the Libya uprising, we are working together to stand up to the murderous Syrian regime and to stop a nuclear weapon in the hands of Iran," Cameron said, in the same pre-summit statement.
On the diplomatic front, France and Britain will press for a stronger UN Security Council position on Bashar al-Assad's vicious crackdown on a popular revolt, despite Russian and Chinese opposition to outside intervention.
The UN General Assembly demanded in a resolution Thursday that Syria halt its crackdown, which human rights groups say has claimed more than 6,000 lives over the past 11 months.
But the largely symbolic text, put forward by Arab states with Western support, was opposed by Russia and China, which just days earlier had vetoed what would have been a tougher resolution by the Security Council.
On the question of practical military cooperation, NATO partners France and Britain plan to review progress on a year-old defence agreement that will see them pooling more resources and technology, especially in naval forces.
According to reports in France, the partners are due to take another step towards building a European armed drone -- an unmanned bomber and spy plane that would be a joint project between France's Dassault and Britain's BAE.
Cameron was due to arrive in Paris shortly before midday (1100 GMT), hold talks and a joint news conference at the Elysee followed by a working lunch.