Tower Hamlets schools are “at risk” of losing more than £5million in the government’s National Funding Formula, according to predicted data.

Described as a “historic reform” by former education secretary Justine Greening, the formula, which comes into effect this month, sees an increase in spending on schools nationally by £1.3billion over the next two years.

But several education unions have been at pains to point out that the majority of schools are still running at a deficit longer term.

According to their figures – based on government data and Institute for Fiscal Studies calculations – the borough’s schools will have lost £15.9m between 2015 and 2020.

That’s the equivalent of losing £277 per pupil over the same period, a rate which is the worst of all of the capital’s boroughs.

The schools predicted to experience the biggest funding pinch in the period between 2015 and 2020 are St Paul’s Way Trust School ( -£1,395,830), Bow School (-£828,868) and Morpeth School (-£744,727).

Most of the schools losing out hardest – due to the number of pupils catered for – are secondaries, but Our Lady and St Joseph Catholic Primary School (-£266,179), Marner Primary School (-£245,015) and Manorfield Primary School (-£236,038) are also set to be hit hard over the five-year period.

Paul Whiteman, general secretary of school leaders’ union of the National Association of Head Teachers (NAHT), said: “We desperately need the government to recognise that overall funding for schools is insufficient. All schools need significant increases in funding.

“Overall we will have a system that might be a bit fairer, but still won’t be transparent or sufficient enough to meet rising costs and growing needs.”

The two key factors behind the union’s calculations are government cash being reallocated across the country, and funding not rising with inflation.

According to the data, all 80 Tower Hamlets schools are facing cuts, with Bonner Primary School (-£5,758), St Paul with St Luke Primary School (-£22,361) and Blue Gate Fields Junior School (-£24,329) set to lose out the least.

To check how your school could be affected, visit schoolcuts.org.uk.