Fourteen migrant children are due to arrive in the UK from Calais to be reunited with their relatives.
They are the first group of minors to be brought over by the Home Office under a fast-track registration scheme – among about 100 expected this week.
They include Afghans, Syrians and stateless Bidun children who originated from Kuwait.
An EU regulation allows them to seek UK asylum because they have close relatives living here.
Under the rules, asylum claims must be made in the first safe country a person reaches, but children can have their claim transferred to another country if they have family members living there.
UK law also requires the government to arrange for the transfer to the UK and support of unaccompanied refugee children from Europe.
On arrival from the Jungle migrant camp in Calais, the children’s first task will be to register with the Home Office in Croydon.
Their families will be waiting for them in nearby churches that have been opened up to host the reunions.
The former Archbishop of Canterbury, Rowan Williams, is one of several religious leaders who will be there to meet them.
It is estimated up to 10,000 people are living in the Jungle, which is situated near the port of Calais, and close to the 31-mile Channel Tunnel.
Many of the migrants in northern France attempt to reach the UK by boarding lorries as they approach ports or the tunnel.
French President Francois Hollande wants to move the inhabitants of the Jungle to reception centres across the country and demolish the camp.
Aid groups have raised concerns that the planned closure will lead to children disappearing before they are processed.
Home Secretary Amber Rudd has said the Home Office is acting urgently to get the child migrants to Britain.
But the charity Citizens UK, which is working alongside the government, is concerned that time is running out to transfer the most vulnerable children before the camp is dismantled next week.
Migrant children to arrive in UK from Calais}