Several dozen migrants have been detained and could be returned to France within weeks, a government source has told the BBC. Earlier Home Secretary Yvette Cooper declined to say how many migrants were being detained under the UK's new "one in, one out" deportation deal with France after crossing the English Channel.

The UK and France will be ratifying their one-in, one-out returns policy on Tuesday after it was announced last month. It means any undocumented person entering the UK on a small boat can now be detained immediately and returned to France.

British border authorities have detained the first group of migrants under a pilot plan that will send some who cross the English Channel on small boats back to France. The migrants