Dominic Raab, the deputy prime minister, held a party for Conservative activists at his grace-and-favour home, raising questions about the costs and whether they were declared within the rules. Raab, who was foreign secretary at the time, invited about 50 Tories from his Surrey constituency to Chevening, a Grade I-listed, 115-room manor, on 4 September for prosecco and canapés. The event was held 20 days after the fall of Kabul and in the wake of criticism of Raab for remaining on holiday as the British army sought to protect its staff. The disclosure comes as a leaked document shows the Tories are doubling the number of regular volunteers campaigning in Raab’s Esher and Walton constituency after his majority collapsed at the last general election. The ministerial code says “government property should not generally be used for constituency work or party activities”. A spokesperson for Raab, now the justice secretary, said the event qualified for an exemption from the rules because the costs were picked up by his constituency party. Section 6.2 of the ministerial code says that “where ministers host party or personal events in these residences it should be at their own or party expense with no cost falling to the public purse”. Raab’s office has not released a breakdown of the costs paid or said when they were paid, or to whom they were declared, as requested by the Guardian. The Liberal Democrat deputy leader, Daisy Cooper, said she would be writing to the cabinet secretary, Simon Case, to ask for a full explanation. “It is staggering that just days after the fall of Kabul, Dominic Raab appears to have been using Chevening House to host a do for his local Conservative party. While Afghan interpreters were desperately trying to escape the Taliban, the then foreign secretary was apparently busy giving a tour of his country mansion to local Tory activists,” Cooper said. “This raises serious questions over whether an official residence has been used to boost local Tory campaigning efforts. Mr Raab must publish details of how much was spent to rent Chevening House, who paid for this visit and whether it has been used to host other local party political events. It shows yet again why Dominic Raab is not fit to be a government minister or to represent the people of Esher and Walton.” The event took place between 1pm and 5pm on Saturday 4 September. About 50 Conservative councillors and activists from Esher and Walton attended the party. Waiting staff carried flutes of prosecco, plates of canapés and wraps to guests who strolled around the lawns, lakes and maze of the 3,000-acre estate in Kent. Photographs show Raab addressing the Conservative activists from the steps of Chevening. On the same day, Taliban forces brought protests by women in Kabul to an abrupt end with pepper spray, teargas and live bullets fired into the air. In the weeks after the fall of Kabul, Raab was heavily criticised for having failed to return from holiday to oversee the crisis amid the reported murder by the Taliban of dozens of people who had worked with British forces. The party was held to thank activists for their work on the 2019 general election. Raab’s majority in Esher and Walton fell from 23,000 to 2,500 as the Lib Dem candidate Monica Harding achieved the biggest swing in the election. The Conservatives are aiming to shore up support in the constituency before the next election. A leaked strategy plan from Raab’s constituency party shows they aim to double the number of regular volunteers in the constituency from 25 to 50 this year and more than double the number of hours by paid-for campaigners from 40 to 104. The document, entitled Esher and Walton Strategy Plan August 2021, also aims to increase membership to 1,000 and send a birthday card from the constituency party to new voters who have turned 18 and are eligible to vote. Raab was demoted to the Ministry of Justice 11 days after the party, but was given the title of deputy prime minister to cushion the blow. Chevening, one of three grace-and-favour mansions temporarily gifted to senior ministers, is usually passed to the next foreign secretary. But after a much-publicised tussle with Liz Truss, the new foreign secretary, over who would have access to Chevening, Raab was told they would share it in future. There appears to be no formal declaration by Raab or the Esher and Walton Conservative party of using Chevening for party political purposes, or any social media coverage. A spokesperson for Raab said all costs of refreshments, staff and venue were covered by the association in full accordance with the ministerial code. No declarations were required and no other constituency events had been hosted there, she added. “An event to thank volunteers in September was paid for in full by local association,” the spokesperson said.