The number of children meeting expected levels of development was lower than pre-pandemic levels last year.

Data from the Office for Health Improvement and Disparities has shown that of the 2,148 children in West Sussex aged between two and two and a half-seen by a health visitor in the final quarter of 2023-24, 365 did not meet the expected level of development.

The figures show that 17 per cent of children in the county are underdeveloped in communication, gross motor, fine motor, problem-solving and personal-social skills.

Although this figure is down from the previous year’s 18 per cent, it remains below pre-pandemic levels, when the figure was 13 per cent in 2019.

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Family Action, a national charity which supports people through change, challenge, and crises, said financial difficulties and a lack of socialisation during the pandemic have impacted children in many ways, while parents are still struggling to find support.

Sue Rogers, head of practice development, said: "Children were born and lived in a very adult world but had tiny developing brains that were trying to make sense of all that was happening.

"Many services around the family now work in different ways, offering online self-help and complex systems that people need to navigate.

"This can mean that many families, often the most in need or in the areas of highest deprivation, will find it difficult to get the support needed for their children.

"This data demonstrates there is still a huge inequality for children and families, and this continues to impact the development of our youngest and most vulnerable in society."

Ms Rogers believes that the government and key decision-makers must put families "at the heart of what they do" and services should work on addressing systemic issues.

A government spokesman said: "Too many children still aren’t meeting the expected standards of development.

"We have already begun this work, confirming that the Nuffield Early Language Intervention programme will continue for another year for any child needing extra support with their speech and language development."