Young children could be at increased risk because of health visitors’ heavy workloads, a union has claimed.

Health visitors in Kingston have caseloads of between 525 and 560 children each, according to the most recent London NHS figures from April 2010.

The figure is above a 400 threshold recommended by the Community Practitioners’ and Health Visitors’ Association (CPHVA) and quoted by Lord Laming in a 2009 report following the death of Baby P.

Health visitors are qualified nurses or midwives who support families during the first five years of a child’s life, and are trained to spot signs of neglect or abuse in children.

All but five of London’s primary care trusts (PCT) exceed the 400 figure, and the caseload figure for Kingston health visitors is average for the capital.

Dave Munday, a professional officer at Unite and the CPHVA, said: “Our belief is that if you get above the 400 figure it becomes very hard to provide the services you would expect.

“At one end, that’s children in danger of significant harm. At the other, it’s about breast feeding and supporting mothers with post-natal depression that often get forgotten.

“Staff have got to have time to make professional relationships with families so they feel comfortable with sharing information.”

Your Healthcare, which provides health visitors on behalf of Kingston PCT, said the figures did not reflect the number of staff nurses and nursery nurses who also work with families, nor the number of children with a protection plan or who are a cause for concern.

The coalition Government has pledged to recruit an extra 4,200 health visitors, and NHS London said health visitor recruitment is a “key priority”.

A spokesman said: "NHS London is undertaking a focussed campaign to recruit health visitors on behalf of organisations across London.

"NHS London is investing heavily to train more health visitors and we are working with all commissioners and providers of health visiting services in London to ensure that the number of health visitors in their area is appropriate to the demographics of the local population."