A quarter of all knighthoods in the New Year honours list have gone to politicians, including the Tory kingmaker Graham Brady, who has Theresa May’s political future in his hands as chair of the 1922 Committee of backbenchers, and former Liberal Democrat leader Nick Clegg.

The annual list makes knights of Brady and Clegg, despite the prime minister’s promise to stamp out the cronyism of the David Cameron era by focusing awards on those who contribute to their community.

Other politicians to get the highest honour include Christopher Chope, a rightwing Conservative who was a junior minister under Margaret Thatcher and John Major, and Geoffrey Clifton-Brown, who served as a junior whip under William Hague. Neither have held any role in the last two governments or even served as committee chairs.

Labour’s Lindsay Hoyle, the deputy speaker of the Commons, is also knighted along with Mark Hendrick, who has served as Labour MP for Preston for 17 years and was previously the first MEP from a minority ethnic background.

The only female MP to get a top honour is Cheryl Gillan, who became the first female Welsh secretary under Cameron. She is made a dame.

The list is notable for not awarding top honours to Tory supporters and advisers, which became a feature during the tenure of Cameron when knighthoods went to his election strategist Lynton Crosby as well as party and remain campaign donors.

However, it continues the tradition of giving out an array of knighthoods to politicians, some of which appear to be on the grounds of their longevity in parliament. Six of the 25 knighthoods this year go to politicians, despite political service being one of eight categories from which to choose. Last year three politicians were rewarded with knighthoods, plus one political donor.

Brady is the most powerful politician on the list, as his role as chair of the 1922 Committee makes him the keeper of any letters of no confidence in the prime minister from Conservative MPs. Once they pass a threshold of 15% of the party’s MPs, it is his job to tell the prime minister that a no confidence vote should be held.

For the moment, May and her Brexit strategy command the support of the Eurosceptic Brady and the rest of his committee.

Another figure close to May who has got a reward in the honours list is Mark Sedwill, who was her trusted permanent secretary at the Home Office and became her national security adviser this year.

Clegg’s knighthood, which was widely reported in advance, is set to be particularly controversial among leave supporters, given his continued campaigning in favour of EU membership and his new book How to Stop Brexit.

Jo Swinson, the deputy leader of the Lib Dems, will receive a CBE, adding to the list of more than 15 of her party’s MPs who have received honours or peerages since the coalition.

The government insists the appointments are made by independent committees mostly composed of civil servants and independent members, but No 10 representatives are allowed to attend and the final lists are approved by the prime minister and the Queen.

This is the first list to be drawn up under new guidance set by May with a renewed focus on making sure it “commands public confidence” and “rewards genuine public service”.

However, the proportion of awards going to people who have undertaken outstanding work in their communities either in a voluntary or paid capacity has fallen from 74% last year to 70% this year.

The proportion of awards going to women has dropped slightly, from 50% to 49%, and to people with disabilities, from 8% to 5%. The proportion of awards going to black, Asian and minority ethnic recipients has remained unchanged at 9%.