Its origin is a biblical quotation.
In a moment, in the twinkling of an eye, at the last trump: for the trumpet shall sound, and the dead shall be raised incorruptible, and we shall be changed.
1 Corinthians 15:52
What’s The So Called Last Trump?
Most post- trib believers equate the Last Trump with the trumpet call Jesus will issue to the angels to gather his elect at the time of the 2nd Coming
I had to Google the passage to get a bit more context and found this is from the opening of The Man in the Queue, by Josephine Tey (published 1929 so now public domain).
Murder
It was between seven and eight o’clock on a March evening, and all over London the bars were being drawn back from pit and gallery doors. Bang, thud, and clank. Grim sounds to preface an evening’s amusement. But no last trump could have so galvanized the weary attendants on Thespis and Terpsichore standing in patient column of four before the gates of promise. Here and there, of course, there was no column. At the Irving, five people spread themselves over the two steps and sacrificed in warmth what they gained in comfort;
I think the sentence is saying that the banging, thudding, and clanking sounds of places opening up are, on the face of it, somewhat unappealing sounds but the queuing theatre goers (weary attendants on Thespis and Terpsichore standing in patient column of four) reacted with great alacrity to them (as one would expect the trumpet call announcing the second coming to be certainly quite a galvanizing event and their reaction to the bangs and clanks is being compared as even greater than that).