Three boats have been intercepted in the English Channel as migrants continue to try to reach the UK.
The Home Office said the vessels were carrying 48 people but has not given details of where they were from.
Dan O'Mahoney, Clandestine Channel Threat Commander, said crossings were organised by "callous criminals who risk people's lives for money".
He said French authorities seized four boats on Tuesday and stopped 21 people from making the crossing.
Mr O'Mahoney said 179 people had been arrested this year for people smuggling.
"These migrants are leaving France which is a safe country, where those seeking refuge can and should claim asylum, rather than attempting these perilous crossings to the UK," he said.
"We continue to return those who do not have a legitimate asylum claim despite barriers to removals under the Dublin Regulation and legal challenges."