More than 300 special-school headteachers have signed a petition calling on the prime minister to boost funding for pupils with special educational needs.

The petition will be handed into 10 Downing Street today, following the first meeting of a new all-party parliamentary group (APPG) for special needs and disabilities (SEND), set up by shadow education minister Emma Hardy.

School leaders’ union the NAHT, which is backing the new APPG, said heads are concerned that special schools are having to fund additional services to support pupil healthcare needs.

Related: Major regional disparity in SEND funding revealed

Special needs: Call for new independent SEND inspections of schools

Analysis: SEND crisis is not just about a lack of money

It said that some schools are having to pay as much as £90,000 per year for one-to-one nursing care for children and young people with the most complex needs. 

“This is a cost that is not consistently supported by health authorities across the country. This is another aspect of the SEND postcode lottery,” the NAHT said. 

“Additionally, rising on-costs for these staff and those in support staff roles, including salary increments have never been supported by recent government injections of funds to schools and LAs [local authorities].”

The petition, addressed directly to Boris Johnson, says: “The children we educate need your attention. The systems and structures in place are unsupportive and devalue the education of pupils with special educational needs and disabilities.

“These children and young people are struggling to have a place in our society and the size of this population is growing.

“They want to live a life and contribute positively. They deserve to have an equal opportunity to thrive and be educated for a better life into adulthood. Without your support and action, this may never happen.”

The petition urges the prime minister to take a direct interest in pupils with SEND by:

• Inviting leaders in the SEND and alternative provision sector to support developments and change.
• Distributing a proportion of the pledge of £780 million to increase [per pupil/place funding] - this has remained stagnant at £10,000.
• Funding the increases to support staff pension contributions and salary increments.

• Holding the healthcare sector to account.

Emma Hardy, MP for Hull West and Hessle, said: “The SEND provision reforms that the government introduced in 2014, whilst worthy in [their] aims, have failed to deliver.

“The government did not provide enough funding from the start and it has left SEND provision in a very precarious position, with some schools having to provide the costs themselves which is not being covered.

“This government is failing the needs of pupils with special educational needs and disabilities, and the SEND provisions in place do not provide our pupils with the necessary support to fulfil their potential.”

Paul Whiteman, NAHT general secretary, said: “The government’s pledge of an extra £780 million for children with SEND, is welcome, and desperately needed. We’re taking this action now because next week’s budget presents a clear opportunity for the government to invest further, as all the research shows they must.”

A Department for Education spokesperson said: “We are increasing high needs funding for local authorities by £780 million next year, boosting the total budget for supporting those with the most complex needs to more than £7 billion in 2020-21.

“No child should be held back from reaching their potential. Our SEND review will look at how we can improve the support children and young people currently receive so the system works for everyone, in every part of the country.”