;2010 election On its creation in 2010, the constituency had, based on complex forecasts involving its three constitutive seats, which factored in to different degrees the recent local election results, a widely varying notional
Liberal Democrat majority (see results
below). In analysis, one forecast suggested that St Austell and Newquay would prove to be a
safe seat, whereas another suggested an extremely
marginal seat. The majority achieved was lower than an average of the two forecasts, but by no means the most slender of majorities achieved in
that election. In 2010, the
Labour Party candidate polled in line with results of the recent decades in the forerunner seats, with 7.2% of the vote.
Mebyon Kernow, the Cornish devolutionist party, achieved its highest share of the vote in any constituency, but narrowly lost its deposit by not reaching the 5% threshold. ;2015 election The seat was won by a
Conservative on a majority of more than 15% which would rarely be termed
marginal; however, approximately half the electorate of the seat fell within areas represented by a Liberal or Liberal Democrat MP between October 1974 and 2015 -
Truro (later adopting a suffix- and St Austell). In terms of the important consideration of length of tenure the seat fails to be describable as in any analysis "
safe". ;2017 election Theresa May announced a snap election would take place on 8 June 2017. In this constituency, Conservative incumbent Steve Double won with an increased majority of 11,142. The constituency also saw a gigantic 18.8% increase in the Labour vote, in common with many south-west seats, pushing the Liberal Democrats into third place. ;2019 election The Liberal Democrats further faded into a more distant third place, with their policy of cancelling Brexit failing to attract voters, in a constituency which voted 64% to Leave the European Union. Unlike many seats across the UK, the Labour vote held up pretty well, with only a 2.6% drop in their vote share.
2024 election The seat was won by
Labour MP Noah Law at the general election on 4 July 2024.
Noah defeated incumbent
Tory representative
Steve Double with a majority of 2,470.
Mr Double blamed the loss on a large
Reform UK vote (Reform UK took 9,212 votes, and came third.) ==Boundaries==