Five asylum seekers were detained after being found hiding inside a lorry.
Off-duty security guard Steve Rook, out with his two daughters, Maryann, four months, and eight-year-old Evie, raised the alarm after hearing banging from inside the lorry as it passed by in Beach Road, Newhaven.
Mr Rook, 38, of Hillcrest Road, Newhaven, said: "I was quite shocked.
"As soon as I heard the knocking on the side of the lorry I figured what was going on. I dialled 999 and police escorted the lorry to the harbour's east quay.
"The lorry driver had spotted me speaking on my mobile and stopped.
"He came running up and said he reckoned he had some people inside.
"We watched the whole thing unfold. Evie thought it was really exciting, watching all the police running around but the little one saw nothing - she stayed fast asleep through it all."
Terry Pullen was driving a Brighton and Hove bus nearby at the time. He said: "The bus was full of passengers going to Eastbourne. Everyone had a good view of what happened.
"After the five were led away police took out their suitcases and other belongings from the lorry."
The five asylum seekers, all adult males, were taken away in a police van.
The men were held at Eastbourne police station and were expected to be interviewed by immigration officials.
A Home Office spokesman said: "If they are deemed illegal immigrants then arrangements will be made to send them back to their country of origin.
"If they claim asylum then they will be detained or dispersed into accommodation while their applications are processed."
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