Conservative Party announced their intention to stand a candidate against Bercow in the next election, breaking the convention of major parties not opposing a Speaker, seemingly in response to Bercow's opposition to Prime Minister Boris Johnson's handling of Brexit. However, Bercow announced in September 2019 that he would stand down as Speaker on either October 31 or at the next election, whichever occurred first. Boundaries and boundary changes 1885–1918: The Municipal Borough of Buckingham, the Sessional Divisions of Ashendon, Buckingham, Newport, and Stony Stratford, and part of the Sessional Division of Winslow. 1918–1950: The Municipal Borough of Buckingham, the Urban Districts of Bletchley, Linslade, and Newport Pagnell, the Rural Districts of Buckingham, Newport Pagnell, Stratford and Wolverton, Wing, and Winslow, and parts of the Rural Districts of Aylesbury and Long Crendon. Gained Linslade and the Rural District of Wing from Aylesbury. 1950–1974: The Municipal Borough of Buckingham, the Urban Districts of Bletchley, Linslade, Newport Pagnell, and Wolverton, and the Rural Districts of Buckingham, Newport Pagnell, Wing, and Winslow. The parts of the Rural District of Aylesbury and the (former) Rural District of Long Crendon were transferred to the County Constituency of Aylesbury. Other minor changes. 1974–1983: The Municipal Borough of Buckingham, the Urban Districts of Bletchley, Newport Pagnell, and Wolverton, and the Rural Districts of Buckingham, Newport Pagnell, Wing, and Winslow. Lost Linslade to the County Constituency of South Bedfordshire. This Urban District of Linslade had been merged with that of Leighton Buzzard to form the Urban District of Leighton-Linslade, which was included in the Administrative County of Bedfordshire. 1983–1992: The District of Aylesbury Vale wards of Bierton, Brill, Buckingham North, Buckingham South, Cheddington, Eddlesborough, Great Brickhill, Great Horwood, Grendon Underwood, Haddenham, Hogshaw, Long Crendon, Luffield Abbey, Marsh Gibbon, Newton Longville, Oakley, Pitstone, Quainton, Steeple Claydon, Stewkley, Stone, Tingewick, Waddesdon, Wing, Wingrave, and Winslow, and the Borough of Milton Keynes wards of Stony Stratford, Wolverton, and Wolverton Stacey Bushes. Rural areas to the north and west of the town of Aylesbury transferred from the County Constituency thereof. The area comprising the new District of Milton Keynes, except for Stony Stratford and Wolverton, formed the new County Constituency of Milton Keynes. 1992–1997: For the 1992 general election, outside the normal cycle of periodic reviews by the Boundaries Commission, the Milton Keynes constituency was split in two, with Stony Stratford and Wolverton being included in the new Borough Constituency of Milton Keynes