Home Secretary Sajid Javid is cutting short a Christmas break to return to the UK to tackle a wave of attempts by migrants to cross the English Channel by boat.
On Friday, Javid declared the situation a "major incident", appointing a "gold commander" to oversee the situation and give daily updates.
But there were calls from MPs for the Royal Navy to be sent in or for Border Force cutters to be brought back from the Mediterranean to target traffickers' boats.
Two boats carrying 12 men from Syria and Iran were brought to shore on Friday, just days after 40 migrants attempted the crossing on Christmas Day.
Immigration minister Caroline Nokes revealed Javid's plan to take personal control of the situation as she visited Dover to speak with Border Force officials on Saturday.
"I can't comment on his whereabouts for security reasons, but he is on his way back and he will be at his desk on Monday," she said.
"He is taking control of the situation and I am in regular contact with him, and we had a conference call just yesterday."
A union representing Border Force staff said it was "very difficult to know" how much the French authorities are doing to prevent people-smuggling from the camps housing migrants in Calais.
"We are being told that those touting for these crossings are absolutely open about it," Lucy Moreton of the Immigration Services Union told BBC Radio 4's Today programme. "They are around and about in the camps, they are in the cafes in those areas of Calais. They are very clear, very open, touting for crossings that night.
"If it's that obvious to journalists and staff in those areas, then presumably it is obvious to the French authorities too."
Ms Moreton said that the two cutters available to Border Force staff patrolling the English Channel were "woefully inadequate" but that adding to their numbers would take a considerable time.
John Woodcock, a member of the House Commons Home Affairs Committee, told The Sun: "The public is losing confidence in the struggling Border Force. It's time to stop the rot by sending in the Royal Navy.
"If the civilian force can't cope, the Navy must stop this crisis becoming a catastrophe."
'A criminal organisation'
Immigration Minister Caroline Nokes speaks with Border Force officers and the HM Coastguard in Dover, to discuss migrants' attempts to reach Britain by small boat. Image: Victoria Jones/PA
Ingrid Parrot, spokeswoman for the French Maritime Prefecture for the English Channel, said the number of illicit crossings in small boats had increased from 23 in 2016 and 13 in 2017 to 70 this year, the majority of them after the end of October.
Ms Parrot told Today: "Before 2018, we didn't have smugglers. But now we have smugglers on the French coast and it is really a network.
"Before that it was not a network, it was individual migrants who were trying to cross. Now it's a network, a criminal organisation."
Ms Parrot said smugglers are using the prospect of Brexit as a way to try to encourage migrants to attempt the perilous crossing before the impending change in UK relations with the EU. Crossings had been "easier" since the end of October because of the mild weather, she said.
She said French authorities exchange "a lot of information" with UK counterparts about smuggling operations, adding: "When migrants call us, we call MRCC (Maritime Rescue Co-ordination Centre) at Dover and Border Force to co-operate at sea to help these people, because we really fear finding bodies on the beach."