Theresa May has paid tribute to the “strong and deep relationship” between France and the UK as President Macron began his first visit to Britain.
The prime minister said both leaders remained committed to the “Le Touquet” border agreement in Calais.
The French president said a new treaty would speed up the processing of adult and child migrants at Calais.
It comes as the UK announced an extra £44.5m to be spent on beefing up Channel border security.
The money will be spent on fencing, CCTV and infrared detection technology in Calais and other border points.
John Pienaar: Why getting on well with France matters
What now for UK-France security relations?
Bayeux Tapestry to be displayed in UK
In depth: The meteoric rise of Macron
But Emmanuel Macron said the Sandhurst Treaty would mean the time taken to deal with adult migrants would fall from six months to one, and for children to 25 days.
Mrs May spoke in French at a press conference to welcome Mr Macron to the UK and praised the “uniquely close relationship between two of the world’s oldest and greatest democracies”.
She said they must demonstrate leadership on military matters and said a combined joint expeditionary force would be ready to deploy up to 10,000 troops “quickly and effectively to face any threat” by 2020.
‘New chapter’
And the prime minister said a multi-million pound deal to build 36 A380 passenger aircraft for Emirates Airlines had been signed by Airbus, which has plants in France and the UK.
She also confirmed that the Bayeux Tapestry will come to the UK in 2022 – a gesture President Macron said he hoped would “open a new chapter when it comes to our cultural cooperation and scientific co-operation”.
He said Brexit would not “impact on the quality” of the UK-France relationship.
The summit between Mrs May and Mr Macron, at the Royal Military Academy Sandhurst in Berkshire, also featured the first meeting of the heads of Britain and France’s five intelligence agencies, and is being attended by UK cabinet ministers and their French counterparts.
