Children with severe learning or motor disabilities are often unable to describe how they are feeling, so parents and doctors have to try and assess how much pain they are in from their behaviour.

Around 10,000 children in the UK with such disabilities are cared for by their parents.

The children can be particularly prone to pains such as heartburn, earache and hip dislocation.

Being able to record the child's behaviour and responses to pain is very useful   Beverly Dawkins, Mencap

Now, experts have come up with a 20-point checklist which can be used to assess how children are feeling.

It covers indicators such as changes in posture, facial expression or sleeping and eating habits.

Parents would be asked to assess their child against the pain profile scale, with each indicator rated between zero and three, when they seemed to be feeling their best and when they were at their worst.

These reference points would then be used by doctors and other carers who did not know the children to help them assess how they were feeling.

Charities have welcomed the tool, which they say will help both parents and doctors who are caring for children with disabilities.

Objective measure

Researchers surveyed 300 families who had a child with learning or motor disabilities.

Almost half said their children experienced pain all of the time, or for periods every day.

Around 20% of children had severe or very severe pain each day.

Dr Anne Hunt, a nurse who has specialised in paediatric palliative care, led the research.

She told BBC News Online existing ways of assessing how much pain children were in were very subjective.

"It's very important to have a more objective way of measuring that."

Dr Hunt, based at the Royal College of Nursing's Institute in London, added: "The scale would be set up with parents. It allows them to describe how they child is when they are in pain and how they are when they are at their best.

This is a huge step forward in the management of children's pain   Action Research charity

"So any future assessments can have a baseline, and healthcare staff would also be able to assess the benefits of treatment."

The research was funded by the charity Action Research and the PPP Foundation.

Action Research's chief executive, Simon Moore, said: "This is a huge step forward in the management of children's pain.

"Action Research is delighted at the positive results of this important project, which will greatly enhance the lives of some of the most vulnerable children in our community."

Beverly Dawkins, Mencap's national officer for profound and severe learning disability, said: "We welcome the scale and we're sure it will be welcomed by a lot of parents with children who have profound and severe disabilities.

"One of the difficulties for these parents is that since their child cannot communicate or describe their pain, when the parents take that child to the GP it can be difficult for the GP to understand how the parent knows their child is in pain.

"Being able to record the child's behaviour and responses to pain is very useful."

It is hoped that parents will be able to get the profile from NHS trusts, and a website is going to be set up so parents can download the form themselves.