MPs are members of the 1922 Committee by default. There are 20 executive members of the committee, agreed by consensus among backbench MPs. The Conservative Campaign Headquarters (CCHQ) is effectively head of the Professional Party and leads financing, organisation of elections and drafting of policy. The Conservative Party Board is the party's ultimate decision-making body, responsible for all operational matters (including fundraising, membership and candidates) and is made up of representatives from each (voluntary, political and professional) section of the Party. The Party Board meets about once a month and works closely with CCHQ, elected representatives and the voluntary membership mainly through a number of management sub-committees (such as membership, candidates and conferences). Membership Membership peaked in the mid-1950s at approximately 3 million, before declining steadily through the second half of the 20th century. Despite an initial boost shortly after David Cameron's election as leader in December 2005, membership resumed its decline in 2006 to a lower level than when he was elected. In 2010, the Conservative Party had about 177,000 members according to activist Tim Montgomerie, and in 2013 membership was estimated by the party itself at 134,000. The membership fee for the Conservative Party is £25, or £5 if the member is under the age of 23. From April 2013 until the 2015 general election people could join Team2015 without being Party members, and take part in political campaigning for the party. At the 2018 Conservative Spring Forum, Party chairman Brandon Lewis announced that the party's membership stood at 124,000. In 2013 the Conservative Party lost an estimated 35–40% of its membership due to the Same Sex Marriage Bill. Prospective parliamentary candidates Associations select their constituency's candidates. Some associations have organised open parliamentary primaries. A constituency Association must choose a candidate using the rules approved by, and (in England, Wales and Northern Ireland) from a list established by, the Committee on Candidates of the Board of the Conservative Party. Prospective candidates apply to the Conservative Central Office to be included on the approved list of candidates, some candidates will be given the option of applying for any seat they choose, while others may be restricted to certain constituencies. A Conservative MP can only be deselected at a special general meeting of the local Conservative association, which can only be organised if backed by a petition of more than fifty members. Young Conservatives From 1998 to 2015, the Conservative