“The Pupil Premium (PP) is additional funding given to all publicly funded schools in England (mainstream and non-mainstream), to raise the attainment of disadvantaged pupils and ‘close the gap’ between them and their peers.” (https://www.gov.uk/pupil-premium-information-for-schools-and-alternative-provision-settings).
Schools are free to spend the Pupil Premium in the way they believe will best ‘narrow the (attainment) gap’ between disadvantaged pupils and their non-disadvantaged peers. Schools are held accountable for the impact of how this funding is being used.