More than 3,800 children with existing statements of special educational needs (SEN) were still waiting for new plans outlining their entitlement to educational support and therapy after the 1 April deadline passed.
Local authorities were told by government in September 2014 that all eligible children with statements of SEN needed to be transferred to education, health and care (EHC) plans by the end of March.
But Department for Education statistics released today show there were 3,873 transfers of SEN statements yet to be completed on 31 March 2018.
The statistics show 232,352 statements (98.4 per cent) had been transferred or discontinued.
The statistics follow an earlier release which revealed that on 1 March 2018, there were 14,305 transfers of statements yet to be completed, meaning decisions had been made on 10,432 statements in just one month.
Quality of EHC plans 'varies widely'
There has been concern about local authorities rushing out EHC plans to hit deadlines.
Ofsted has said that the quality of plans varies widely between different areas and, even when plans were completed on time, often theyincluded “too much confusing terminology and jargon” or could be too general.
The government has said previously that any statement of SEN for which a transfer review has not been completed by 1 April will remain in force to ensure that children and young people in this situation do not lose support.
But there have been previous warnings about delays in the system, with the local government and social care ombudsman saying earlier this year that children could wait up to 90 weeks for their statement to be transferred to an EHC plan.
Educational psychologists, who have a statutory role in the process, have said that the deadline was not likely to be met because there were not enough in their ranks.