The Government will provide £12m over the next three years to deal with illegal immigrants trying to get to the UK from Calais.
Home Secretary Theresa May and her French counterpart Bernard Cazeneuve reached a deal which will also see increased co-operation between British and French law enforcement agencies.
They also agreed to do more to tackle organised gangs involved in people trafficking and smuggling.
Security and Immigration Minister James Brokenshire said the two countries would also "continue to push for action at European and international level to address the wider problem of illegal migration, of which Calais is just one very visible sign".
The family of a jailed Pakistani scientist nicknamed Lady al Qaida, whose release has been demanded by Islamic State (IS) extremists, has urged the militant group to free two British hostages.
Dr Aafia Siddiqui's sister, neurologist Dr Fowzia Siddiqui, pleaded for IS to spare British aid worker Alan Henning and photojournalist John Cantlie along with others they are holding.
She told the Daily Telegraph: "She (Aafia) would be distraught if she knew that there are people bragging about murder and mayhem and using her name to justify it.
By Amanda Houston, ITV Weather presenter.
Further heavy thunderstorms are expected in southern areas this afternoon, with the risk of localised flooding.
Elsewhere it's a mixture of isolated showers and bright spells. The best of the sunshine will be in Scotland, Northern Ireland and north-western areas.
It will feel cooler than recent days, maximum temperature 20C.
Rain will clear the south throughout tonight with clear spells developing in many places.
It should be much cooler than last night with temperatures falling down to 5C in some rural areas.
A much quieter, fresher but brighter day follows on Sunday.
Lightning strikes sparked a fire in the roof of St Michael's Hospital, Rayne Road, Braintree amid storms that swept across the south east, Essex County Fire and Rescue Service said.
Part of a hotel roof has collapsed after a blocked drain caused water to pool, the Essex County Fire and Rescue Service said.
Former Prime Minster Gordon Brown has said that there is a "time to fight and a time to unite" as he called on Scotland to look to the future.
Police investigating the disappearance of teenager Alice Gross are urging local businesses with CCTV cameras to come forward with any footage that may help with the search.
ITV News reporter Sejal Karia is following the latest developments.