Aug. 7 (UPI) -- A landmark Anglo-French "one-in, one-out" migrant agreement saw the first small boat arrivals on the British coast taken into custody in preparation for being returned to France, the government said Thursday. The detentions got underway on Wednesday with migrants who had crossed the Channel "illegally" held in secure immigration centers pending their removal to France, which was expected to take place in a matter of weeks, according to a Home Office news release . It pledged