The Covid-19 Bereaved Families for Justice group has been allowed to attend to the Conservative party conference after it was left “shocked and frustrated” at initially being refused access. The organisation, which represents more than 4,000 bereaved families, wants to lobby MPs at the October event in Manchester amid frustration that it has still not met the prime minister or the health secretary despite multiple requests to do so. Six weeks after seeking accreditation to the conference, the group’s application was rejected. It received an email from the party chairman’s office saying that it did “not comment on the reasons behind an individual’s or group’s unsuccessful conference application”. But after being contacted for comment by the Guardian, the Conservatives said they had now informed the group it could attend and that the initial rejection was an error that had subsequently been reviewed. The group says it represents bereaved families from all political backgrounds, including members of the Conservative party. It has been calling for an urgent public inquiry into the UK’s handling of the Covid-19 pandemic and greater bereavement support. It initiated the national Covid memorial wall of more than 150,000 hand-drawn red hearts – one for each of the UK’s Covid dead – on the South Bank of the Thames opposite parliament. “It defies belief that the party in government seems determined to not only ignore us but have as little contact with us as possible,” said the group’s spokesperson Lobby Akinnola after the initial refusal. “Being treated like this is deeply upsetting for families who are already in grief.” Akinnola whose care worker father, Olufemi, died from Covid in April 2020, said: “The question we’re left is asking is: ‘What are the Conservative party management afraid of?’ It might be more comfortable for the Conservative party to pretend that groups like ours don’t exist, but we do and it is basic decency to talk to us. “We had hoped to attend party conferences so that MPs from all sides could hear our stories and work with us to learn lessons and stop more families from experiencing the same tragedies that we have. Ultimately, we all have the same goal.” Speaking after the U-turn, Akinnola said: “Their initial decision to disallow bereaved families from attending was disgraceful, and we hope that there is a genuine acknowledgement of that and that they are prepared to work with us. “Laughably, they’ve claimed the initial decision was ‘an error’. Funny that the error wasn’t spotted when we initially asked for an explanation for the decision, and only when the news broke in the media.” The group said it had not yet been able to secure any meetings with Conservative government ministers. Boris Johnson is yet to meet it, a year after he first said he would. Sajid Javid, the health secretary, told the group he was “too busy” to meet them earlier this year, the group said. Hundreds of lobbyists for private industry, from banking to housebuilders, will attend the Tory conference, which starts on 3 October. The bereaved group applied for a single organiser to attend with the intention of trying to persuade delegates that the longer an inquiry is delayed, the longer vital lessons are not being learned, and that key evidence may be lost or destroyed. Johnson announced earlier this year that a statutory public inquiry into the pandemic would begin in spring 2022, but no further details have been made public about its terms of reference or the chairperson and panel that will oversee hearings, which could take years to complete.