The Home Office said tonight that 13 people found in a lorry in Kent, whose nationalities have yet to be confirmed, will be questioned later.
Officials had this warning for lorry drivers entering the UK:
Drivers and hauliers must take adequate steps to secure their vehicles from illegal immigrants trying to smuggle themselves across the border.
If a driver does not take these steps - and is found with people hiding in their vehicle - they will be issued with a civil penalty.
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The new scheme aims to speed up the permission process and allow applicants to apply from overseas and work in Ireland.
Since January 2010 there have been 35 collisions on the Thames involving older boats.
IPPR North research says the figure rises to seven times per person when compared with Yorkshire and the Humber or the North East.