Angela Rayner has been given a permanent seat on the UK government’s national security council as the rebooted Downing Street operation seeks to smooth over reports of tensions between Keir Starmer and his deputy. Allies of the deputy prime minister had shared concerns she was being sidelined when it emerged two weeks ago that she had been given only a temporary place on the committee that brings together ministers with military and intelligence chiefs. However, the Guardian understands she has now been made a permanent member of the NSC, which discusses and assesses the biggest threats facing Britain, as part of a concerted effort driven by the new No 10 chief of staff, Morgan McSweeney, to bolster her position. Starmer has also strengthened the “quad” of his most senior ministers to become a proper steering group for the government’s agenda, insiders said. As well as Rayner, it includes Rachel Reeves, the chancellor, and Pat McFadden, the senior cabinet office minister. In another move to shore up the deputy prime minister, she will more formally and routinely deputise for Starmer, for example by standing in at prime minister’s questions this week, while he is away in Samoa at a Commonwealth heads of government summit. Downing Street hopes the changes will reassure the deputy prime minister, and her allies in the Labour party and across the union movement, that she has Starmer’s full support, after reports of continuing tensions between the pair. A No 10 source said: “Keir respects Angela and wants to make sure that is recognised more widely in government.” Others downplayed suggestions that Rayner and other cabinet ministers writing to Starmer to protest at cuts to their departments, set to be unveiled at next week’s budget, was anything other than part of the normal process. A second government source said: “Nobody on either side wants any more drama.” There has long been speculation among some of those around Starmer over his deputy’s own motives, with suspicions that she could be on manoeuvres to be in prime position to take over from him at some point in the future. Her allies said the latest changes were led by No 10 itself after the promotion of McSweeney, and should be seen as an attempt to better manage the relationship between Starmer and one of his most powerful ministers. Officials said that while Sue Gray, McSweeney’s predecessor as chief of staff, had been supportive of Rayner personally and of her role in principle, that did not always transfer into practice, with promises not always being delivered on. One described it as a “mismatch”, but suggested that it may have been down to broader dysfunction within Downing Street at the time. Earlier this month, it emerged that seven permanent members had been chosen to attend the NSC meetings, including Starmer, Reeves, McFadden and David Lammy, the foreign secretary. Yvette Cooper, the home secretary, John Healey, the defence secretary, and Richard Hermer, the attorney general, were also named as members. However, Rayner’s absence from the list fuelled claims that she had been sidelined by No 10 since Labour’s general election victory. Previous deputy prime ministers, most recently Conservative MP Oliver Dowden, have been permanent members of the NSC.