A "one in, one out" deal agreed by the UK and French governments on Thursday proposes that for each migrant the UK returns, Britain will accept another who has made a legal claim in France.

Britain will grant asylum to one migrant in France who can prove a family connection to the U.K. in exchange for each arriving migrant taken back by France.

Home Secretary Yvette Cooper said people who arrive on small boats will be detained as part of a 'groundbreaking' one-in-one-out returns deal with France - but refused to say how many would be affecte