More than three-quarters of children with special educational needs faced delays in getting plans as they prepared to move into high school.
St Helens Council was named among 103 local authorities that failed to deliver all the plans by the statutory deadline of February 15.
Their opportunity to review and challenge the provision set out in these plans is severely hampered if they are not provided on timeSolicitor Samantha Hale
Figures obtained under the Freedom Of Information Act by lawyers Simpson Millar show 21 children in the borough needed an education health care plan or statement of special educational needs for transitioning from primary to secondary school in September.
But 16 of those plans - 76.19 per cent - were not completed in time.
The data shows that nationally 2,405 children were waiting for their plans, with 62 councils failing to issue them to 10 or more children.
Education solicitor Samantha Hale, from Simpson Millar, said: “Parents of children with special educational needs are understandably often anxious about school changes, and their opportunity to review and challenge the provision set out in these plans is severely hampered if they are not provided on time.
“This is a statutory deadline, put in place to ensure a sensible and managed transition for children who otherwise might find the whole thing very stressful. If the plans are not issued on time, parents who wish to appeal the provision set out in it might not be able to have it heard by the tribunal.”
A St Helens Council spokesman said: “The local authority was aware that the EHCPs would not be completed by the deadline, however all parents have been fully informed and consulted on their preference throughout the process.
“The vast majority of children with EHCPs are in specialist placements where pupils remain at the same school and so do not transfer from one school setting to another during their transition, and discussions with parents determined that they would remain in these to ensure continuity of education. This was formally confirmed in a letter to parents and then reiterated in their EHCP.
“Eighteen out of 21 families were offered their first choice of school, with parents happy with the outcomes. The three remaining families appealed and will be heard by the SEN tribunal in September, with a view to finalising their placements early in the school term.”