The Labour conference could cause a crisis for homeless people in East Sussex as guest houses are swamped by delegates.
Homeless families in Seaford have been told there is no temporary accommodation for them in the area until it is over.
One family, currently staying in a bed and breakfast in Seaford, will have to leave their temporary home to make way for conference visitors to Brighton.
The owner of the establishment, who asked to remain anonymous, said he housed a woman with a young child last week.
He admitted she would have to be moved by the beginning of the conference on Sunday because he had a prior booking.
Another family has been told to move to temporary accommodation in Crowborough.
Housing officers told Faye Sayers, 24, that she and her three-year-old son Joseph would have to go out of the area because of the shortage in the Hove to Seaford area.
She said: "They told me that because of the Labour Party conference all the bed and breakfasts in the area were full.
"They said families had been asked to leave accommodation to make way for delegates."
Miss Sayers and her son, who both have chronic asthma, are now living in a one-bedroom flat in Seaford with Miss Sayers' mother, Jill, and partner, Lee Robins.
They say a move to Crowborough would interrupt Joseph's nursery schooling and split up the family.
Jill Ticehurst, Lewes Council principal housing needs officer, admitted the conference had put pressure on bed and breakfast accommodation for the homeless.
She said: "It's true there are no bed and breakfast vacancies in this area until after the conference.
"We have only limited vacancies for the homeless people in the local area.
"We first try to find accommodation in Brighton and Hove and then Eastbourne, but we may have to look further afield."
A spokeswoman for Shelter, the charity for the homeless, said: "Whether it's tourism or a conference, if a big influx of visitors can disrupt bed and breakfast accommodation for the homeless, it shows how fragile the system is."
A single mother from Brighton is also angry at being told to move out of her room at a Brighton seafront hotel to make way for the Labour Party Conference.
She is one of five families being forced to move out of the King's Hotel.
She said: "I feel completely powerless. It's very disruptive for the children."
A Brighton and Hove Council spokesman said: "More and more people are coming to us because they have found themselves homeless. We are running out of options as to where to house them."
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