Asylum seekers were found "highly distressed" and "completely lost" after being transported from a processing centre in Kent and dropped of in central London with nowhere to stay.
The 11 men were driven to Victoria coach station from the Manston centre on Tuesday as part of a larger group, as the i and Guardian newspapers first reported.
They were eventually helped by Danial Abbas, from the Under One Sky homelessness charity.
He told ITV News that when he spotted the 11 men, he immediately noticed “something was really wrong”.
"The people who were on the coach were individuals who had a contact - family and friends' address in London where they could go and stay until their asylum interview," he said. “But within that group there were 11 people who didn’t have an address, any family or friend that they could go to."
Mr Abbas said the 11 had been told that they'd be given hotel accommodation in London, but were dropped off at Victoria station without an address to go to.
Mr Abbas said that when his charity contacted the Home Office, it acknowledged it had made an "error".
A Home Office spokesperson told ITV News: “The welfare of those in our care is of the utmost importance and asylum seekers are only released from Manston when we have assurances that they have accommodation to go to. Any suggestion otherwise is wrong.
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“We worked at pace to find accommodation for the individuals as soon as we were notified, and they are now being supported.”
The 11 men were taken by taxi to a hotel in Norwich, where Mr Abbas said they have since received hot meals and now have "smiles on their faces".
The men were among hundreds of people thought to have been moved out of Manston – a disused airfield site near Ramsgate – amid concerns it had become dangerously overcrowded.
Raising a point of order in the Commons on Wednesday, Liberal Democrat MP Alistair Carmichael said: “On Monday … the home secretary said ‘What I have refused to do is to prematurely release … thousands of people into local communities without having anywhere for them to stay’.
“It is reported today that last night exactly that happened. A bus full of detainees was taken from Manston to Victoria Station, where they were then left abandoned and apparently one was left to sleep rough overnight.
“That surely contradicts what the home secretary told the House. She has something to answer."