Every primary school child in Scotland is to get a yearly obesity check as part of a plan to tackle the country's health crisis.

The SNP are to vote at their annual conference this weekend on a scheme for regular weight and height checks for all primary pupils, which will provide information to calculate their body mass index (BMI) to determine if they are overweight or obese.

This information would then be used to develop exercise or diet regimes which would also involve their parents.

At the moment, all children have their height and weight measured when they arrive at primary school and their BMI is calculated. However, this is done only once, and the information is only used for compiling national statistics. If obesity is detected, the child's parents are not told and neither is the school.

The plan, which is still in its early stages, has been cautiously welcomed by health experts and opposition politicians but it has been warned that the information had to be used sensitively to avoid stigmatising those children deemed overweight or obese.

Scotland has a poor record on childhood obesity with recent figures showing more than a fifth of primary one children in Scotland overweight, 8.5% obese and 4.3% severely obese. By the age of 12, more than a third are overweight, including almost 20% who were obese. 

The Scottish Government has already introduced new measures, including a move towards free school meals for the early years of primary schools and more exercise time in the school day.

Despite this, Scotland has retained its place as the fattest nation in the UK and experts warn of a time-bomb, with large numbers of overweight children becoming obese in later life.