Senior politicians have written to the leadership of Pimlico academy, the London secondary school at the centre of protests over allegations of race discrimination, to express concern over plans of possible disciplinary action against protesting students. Hundreds of students took part in a demonstration outside the school last month over changes to the curriculum, uniform policy and the siting of a union flag outside the academy building. The students who organised the protest were told last week that they could face permanent exclusion and were asked to attend a disciplinary meeting on the first day of term. It is understood that some of the disciplinary meetings have since been rescheduled and the school has reiterated that they would be approached from a “reconciliatory perspective” and that at present no exclusions have resulted from the protests. In a letter to the headteacher, Daniel Smith, on 19 April, dozens of MPs including Diane Abbott, Jeremy Corbyn and Dawn Butler, expressed their deep concern about possible action against children who had taken part in the protest. Their letter urged the school leadership to reconsider its position on disciplinary action, and said the students had chosen to exercise their rights to protest within a “long and proud tradition”. “In doing so, students and young people should be treated with respect, not reproach. As members of parliament, it would concern us deeply if their faith in democratic principles were shaken by incidents like these, rather than nurtured,” it added. Abbott said: “A number of us were really shocked by the letter where children were potentially being threatened with permanent expulsion, but these children have a right to express their views … It is very wrong to threaten children in this way who are standing up for something that they believe to be an injustice.” The Pimlico Parent Group said in a statement that the Easter holiday had not been the period of quiet reflection they had hoped it would be. “The letters from Lord Nash and Daniel Smith, implying disciplinary action against the ‘ringleaders’, have not had a calming effect. We fully support our children in their actions during the protest and do not want the ‘ringleaders’ of the protest to be disciplined,” the statement said. Describing the protest on 31 March as peaceful, primarily because of the “influence of the older students”, it added: “We want Pimlico academy to return to normality as quickly as possible. Change is required … for the good of our children and their futures, not for the management of the school.” Former alumni have also written to the school trust, Future Academies. In an open letter sent via email more than 30 said they stood in solidarity with current students and called for the resignations of Smith, and chairs of the trust, John Nash and his wife, Caroline. The National Education Union (NEU), which represents teachers at the school and has previously passed a motion of no confidence in Smith, also pledged its support for the students. The Pimlico NEU said in a statement sent to staff and shared with the Guardian that it too stood in solidarity with students who had protested peacefully on 31 March. “We oppose any reprisals for students who participated in the protests … the right to strike and protest are fundamental democratic rights to students and workers alike,” it said. Nash sent a letter to parents before pupils’ return to school on Monday warning that any future disobedience would result in disciplinary action. His letter was strikingly different in tone to one Smith had sent immediately after the protest, in which he expressed regret but also admiration for his students who were “passionate about the things that matter to them”. Students took down a union flag that had been erected outside their school in September last year. Four weeks earlier, they had started a petition in response to the academy’s strict new uniform policy, which stated that hairstyles that “block the views of others” would not be permitted and hijabs should not be “too colourful”. The pupils accused the school’s management of racism, saying the new policy would penalise Muslims and those with afro hairstyles.