The Conservatives are bracing themselves for a slew of departures by MPs, with many expected to be announced by the end of the year, as the former work and pensions secretary Chloe Smith became the latest to decide not to stand at the next election. Her decision came before a December deadline for parliamentary candidates to tell Conservative headquarters (CCHQ) whether they are planning to run again in 2024. Later on Tuesday, senior backbench MP William Wragg announced via Twitter that he would not stand again in Hazel Grove at the next election. The Guardian understands MPs have been asked to indicate their preferences for the next election by 5 December, which also marks the closing of the final consultation on the boundary review. The party is hoping to begin making preparations for parliamentary selections, as well as find solutions for MPs whose constituencies are affected by the review. Smith, 40, won her Norwich North seat in a 2009 byelection against Labour and increased her majority to 4,793 in 2019, but had a tiny majority of just 507 votes in 2017. On current polling, Smith would be likely to lose her seat to Labour. Wragg holds his Cheshire seat by a majority of 4,400 over the Liberal Democrats, who held the constituency from 1997 until Wragg took it in 2015. In August, Wragg said he was taking a short break from his duties because of a period of severe depression and anxiety. Smith was briefly in the cabinet under Liz Truss and held a variety of junior ministerial positions but returned to the backbenches when Rishi Sunak became prime minister. She was the youngest member of the Commons when first elected at the age of 27 and also had a bout with breast cancer during her time as an MP. She said in a statement: “I hope I’ve been able to make a difference, locally and nationally. In 2024, after 15 years of service, it will be the right time to step back, for me and my young family.” Labour has already given its MPs a deadline to declare whether they are standing in the next election, which has led to a number of high-profile announcements from retiring MPs including Harriet Harman, Rosie Winterton, Margaret Hodge, Margaret Beckett and Ben Bradshaw. Two other veteran Tories, Crispin Blunt and Sir Charles Walker, have also announced they will stand down at the next election. But senior Tories have privately predicted there are likely to be at least 30 MPs who will not seek re-election, with some saying the number could be as high as 80. Recent opinion polls, including on sites such as Electoral Calculus, predict the Conservatives could lose more than 200 seats, although Labour has said it expects polls to narrow over the next 18 months. But Conservative MPs have said a 20-point lead for Labour would result in significant numbers of those in previously safe seats losing their jobs, including those with a majorities up to 15,000. About 10 current or former cabinet ministers including Jacob Rees-Mogg, Dominic Raab, Thérèse Coffey, Jeremy Hunt and Simon Clarke would lose their seats in a general election on current trends. Others include: the Foreign Office minister Anne-Marie Trevelyan; Alok Sharma, the Cop26 president; Jake Berry, the former Tory party chair; and Robert Buckland, the former Wales secretary. Boris Johnson, the former prime minister, is also on course to lose his seat, along with the vast majority of the “red wall” MPs who entered the Commons after the 2019 election. Some high-profile MPs have suggested they may not fight the next election, including Michael Gove, who said after the departure of Johnson that he believed his time in frontline politics to be over. But under Sunak, Gove has returned to the Department for Levelling Up, Housing and Communities.