Commenting on a link to Conor Pope, "New poll shows Labour support nose-diving", Irish Times 3/30/2013, B.H. remarks that "If I knew what it was, I might do it for them …"
The obligatory screenshot:
The OED's entry for nosedive indicates that it originated in reference to airplanes: "Aeronaut. A steep downward descent by an aircraft with the nose first". The earliest OED citation is from1912:
1912 Flight 31 Aug. 787/1 The machine at once started a spiral nose-dive.
1917 ‘I. Hay’ Carrying On i. 17 Next moment she [sc. the aeroplane] lurched again, and then took a ‘nose-dive’ straight into the British trenches.
Note that the joke is better in varieties of English that use plural verb agreement with singular collective nouns like "Labour".