Britain and France are due to sign two new defence treaties today agreeing to the joint development and testing of nuclear warheads. Prime Minister David Cameron and President Nicolas Sarkozy will also outline plans, at a London summit, for a joint army expeditionary force. The plans will see one centre set up in the UK to develop technology and another in France to carry out testing. A Downing Street spokesman said the summit marks a deepening of the UK-France bilateral relationship. The summit comes two weeks after the UK government announced cuts to its armed forces, in the first strategic defence review since 1998, as part of savings aimed at reducing the country's budget deficit.