The situation at the Manston migration centre in Kent is a "breach of humane conditions", according to the Tory MP for the area.
Conservative backbencher Sir Roger Gale told Sky News overcrowding at the facility - where outbreaks of MRSA and diphtheria have been reported - is "wholly unacceptable".
The site is only designed hold 1,000 people but there are currently around 4,000 migrants there - more than the size of any UK prison population. Hundreds more people were moved there yesterday, following a petrol bomb attack at the Border Force Migration centre in Dover.
Home Secretary Suella Braverman is coming under scrutiny for the worsening situation, following a report in The Times which claimed she blocked the transfer of asylum seekers from Manston to new hotels and ignored legal advice that the government was illegally detaining people there.
Asylum seekers are meant to be in Manston, a disused airfield, for no longer than 24 hours while they undergo checks before being moved to immigration detention centres or asylum accommodation.
But Sir Roger said "as a result of Home Office policy, that (system) is now broken".
The MP for North Thanet said he visited the site on Thursday and things are "much worse" than the week before "when there were two and a half thousand people".
He said: "These circumstances, I believe now were a problem made in the Home Office."
Sir Roger said that until around five weeks ago, the system was "working as it was intended", but it was "now broken and it's got to be mended fast".
He called for an end to "dog-whistle" politics and said actionable solutions were needed instead.
Asked if Ms Braverman was the right person to be leading the Home Office, Sir Roger said he was not going to "point fingers", but that "whoever is responsible, either the previous home secretary (Priti Patel) or this one, has to be held to account".
"A bad decision has been taken and this has led to a breach of humane conditions."
Sources close to Priti Patel have told Sky News the former home secretary signed off transfers of migrants from holding centres to hotels throughout the summer, saying she had a statutory duty to do so.
Sir Roger said he has put forward an urgent question in the Commons to be answered by Ms Braverman or Robert Jenrick, the immigration minister.
Mr Jenrick visited Manston on Sunday after another watchdog, Chief Inspector of Borders and Immigration David Neal, told MPs he was left "speechless" by the problems at the site.
The Home Affairs Select Committee heard conditions at Manston were "wretched", with overcrowding, outbreaks of diseases and people being held for as long as a month.
Environment minister Mark Spencer told Sky News the UK needs to find a way to deal with migrants "compassionately" as he acknowledged there are "huge challenges" in the system.
Asked about the reports Ms Braverman blocked transfers of people out of Manston, he claimed this was done to "speed up applications" and make sure only "genuine" asylum seekers are admitted to the UK.
He added that the way to cut down on migrants crossing the channel is to "break the model" of people traffickers.
His interview has been somewhat overshadowed after he suggested "some little man in China" was listening to his phone calls, in response to a question about reports Liz Truss's phone was hacked while she was foreign secretary. This has lead to criticism from Labour MPs who accused him of "ignorance" and "casual racism".
'Entirely fresh approach needed'
Labour has also called for Ms Braverman to take action and "make decisions" on migration to solve the current crisis.
Shadow home secretary Yvette Cooper said a "failure to make decisions" within the government had left people waiting for lengthy periods in supposedly temporary accommodation.
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Ms Cooper claimed the home secretary had not made a proper statement on the crisis as there were still questions over her "own security breaches" - after her initial resignation for sending government information via a private email.
Pressure is piling on the Home Office as a record of number of people continue to cross the channel, with 1,000 migrants arriving on Sunday.
The Home Office is already grappling with a 100,000 backlog in processing asylum applications, with 96% of those from last year still outstanding.
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Officials have noted a surge in illegal migration from Albania, which has been blamed on criminal gangs having a "foothold" in northern France.
On Sunday, refugee charities wrote to the home secretary demanding the government create more safe routes to the UK as a solution to stopping the dangerous small boat crossings.
Meanwhile Kevin Saunders, former chief immigration officer for the UK Border Force, said the system is "broken" and that he would put asylum seekers on a cruise liner.
And Conservative MP for Dover, Natalie Elphicke, said an "entirely fresh approach" is needed to tackle the "out of control" crossings in small boats.
She told TalkTV: "In the most immediate term that does mean stopping the boats leaving France. There are obviously a whole range of other measures, but at the moment a number of those are held up in the courts, a number of those are subject to more legal changes to go through Parliament, so all efforts have to go on stopping those boats and tackling the issue head on."