MPs have launched an inquiry into the rising number of people trying to enter the UK using small cross-Channel boats.
More than 1,000 migrants arrived on UK shores in this way in July, while 235 were detained this Thursday - the record for a single day.
The Commons home affairs committee will look into the criminal gangs who run crossings, the dangers passengers face and UK and French government actions.
Labour said ministers were "failing to get to grips with the crisis".
The committee will assess the conditions migrants face in France - where they often stay in makeshift camps while they wait for boats - and the particular dangers to children who make the crossing unaccompanied.
In a tweet, Home Secretary Priti Patel said the number of crossings was "unacceptably high".
"I know that when the British people say they want to take back control of our borders - this is exactly what they mean," she added.
She said "genuine refugees" would be able to claim asylum in other "safe" EU countries.
Speaking to Sky News, Chancellor Rishi Sunak did not deny reports the Royal Navy could be used to patrol the English Channel for migrant boats.
"I'm frustrated," he said. "Everyone is, which is why we've been working much more closely with the French government in recent time to improve our co-operation and intelligence-sharing to police crossings."
The number of people making the crossing in July was almost as high as the combined total for May and June, with migrants encouraged by good weather and calm seas.
Natalie Elphicke, Conservative MP for Dover, Kent, tweeted that the "unacceptable situation" must be "brought to an end".
Labour's Rosie Duffield, who represents Canterbury, said the numbers represented those "whose terror at making this most treacherous of crossings was still not as horrific a concept as staying in the place where they were".
Labour's shadow home secretary Nick Thomas-Symonds said the crisis was "deeply concerning".
The committee, chaired by Labour MP Yvette Cooper, has previously questioned Mrs Patel on the issue, but will now conduct a full inquiry.
Ms Cooper said she was concerned about "criminal gangs" who were "making money from putting people in flimsy dinghies".
She said it was "particularly troubling to see children being put at risk" and the committee was taking written evidence in preparation for Parliament's return in September, when it will hear oral evidence.