The Department for Education identifies disadvantaged pupils as:

• Eligible for Free School Meals or have been in the last six years
• Looked After Children (LAC), or those who have previously looked after by the state, but are now adopted or are subject to a special guardianship order, a child arrangements order or a residence order
• Children with parents in the armed forces.

It is assumed that these children are disadvantaged in comparison to others because of low family income, little or no family support (LAC) or lots of school moves all of which have been proven to have a negative impact on progress and attainment when compared to others.
The Government provides funding, the Pupil Premium, to allow schools to put interventions into place to try to close the gap between disadvantaged pupils and their peers.