Parents voiced their anger against a council for not keeping them informed about plans to close a school.
More than 100 people packed a school hall to hear a public consultation about proposals to merge Freshbrook First School with Thornberry Middle School, both in Lancing.
The education shake-up would create 11 all-through primary schools in the Adur District instead of the present 17 first and middle schools.
Adur is one of the few districts in the country where children go into secondary education at 12, meaning their key stage 3 learning is split between middle school and secondary school.
West Sussex County Council wants children to leave the primary schools at the age of 11 instead of 12, which would bring them in line with the rest of the country.
At last night's meeting at Thornbrook School, Freshbrook Road, plans were revealed to parents of both schools.
But parents told members of the Local Education Authority they felt they had been "uninformed".
One said: "We haven't been told anything, we haven't received so much as a letter."
Marie Maskell, 35, an accountant, from Lancing, has one child at Thornberry Middle School and one child at Freshbrook First School.
She said: "I came here tonight thinking they were going to have plans and give us some information but we didn't get anything. They did not have any answers and I don't think we have been told much at all.
"I agree with the all-through primary schools in principle but unfortunately it's at the cost of my child's education as he will have to move."
Her husband Paul Maskell, 38, added: "What is the point of them bringing us here to ask us what we think if they don't have any information?"
Lorraine Overington, 36, from Lancing, said: "I have a daughter at Freshbrook. I don't agree with this at all. I think things are fine the way they are.
"They are saying class sizes are not going to get any bigger but they will. They should employ more staff and invest more."
Norraine Woolgar, 42, added: "I have a special needs son at Freshbrook and I am concerned he will get lost in the system. It is hard enough for him to cope as it is without bigger classes."
Phil Whiffing, school organisation planning manager for West Sussex County Council, said: "Effectively we would close both schools and open a new one on the Thornberry site. There will be a new governing body which would appoint a headteacher and staff. This will result in children having a better education and experience all the way through."
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