More than 100 migrants, claiming to be Iranian, have attempted the dangerous journey by small boat to the UK in the past three weeks. Why?
On 23 November, shortly before sunrise, eight migrants were found clinging to a dinghy in choppy waters off the coast of Kent.
They told their rescuers they had spent 12 hours at sea.
It was a similar story the day before, when seven more were found in a boat just off the Dover coast - the same number of people had been pulled from an inflatable boat just a few hours earlier.
Since 3 November, 101 migrants - including four children - have attempted the 21-mile journey across the Channel, one which police have likened to "trying to cross the M25 at rush-hour on foot".