The suspected migrants are believed to have arrived off the Kent coast on several boats and were brought ashore at Dover.
Ninety migrants have been intercepted while trying to reach the UK, including women and children.
It is the biggest surge of migrants intercepted in the English Channel and Dover in any one day.
The Home Office said 15 of the 90 migrants claimed to be minors.
They arrived off the Kent coast on several boats and a large-scale search and rescue operation was launched by British and French patrol boats.
Witnesses said some were carried off on stretchers to waiting ambulances, while others wrapped in blankets were checked over by paramedics.
HM Coastguard told Sky News it responded to "a number of incidents" off the coast, along with Kent Police, Border Force and other agencies.
Footage from the scene showed people being escorted off the Home Office's patrol cutter Searcher.
Border Force said in the first incident, at around 2:15am, one of its vessels intercepted a rigid-hulled inflatable boat (RHIB) which was carrying a group of five males who presented themselves as Senegalese, Malian and Guinean nationals.
The force said in the second incident, also at around 2:15am, one of its vessels intercepted an RHIB which was carrying a group of 21 males who presented themselves as Syrian, Yemeni and Egyptian nationals.
Border Force and partner agencies said dealt with a further six small boat incidents today.
In one incident, at around 7:40am, a vessel intercepted a boat which was carrying a group of 12 males and females who said they were from Iraq and Iran.
In another incident, also at around 7:40am, a Border Force vessel intercepted a boat that was carrying 16 men who also said they were from Iran and Iraq.