A forlorn hope

(Mil.) a body of men (called in F. enfants perdus, in G. verlornen posten) selected, usually from volunteers, to attempt a breach, scale the wall of a fortress, or perform other extraordinarily perilous service; also, a desperate case or enterprise.

See also: Forlorn

References in classic literature ?
I do not forget them," replied Carthoris, but he did not tell Jav that he remembered something else that the Lotharian had let drop--something that was but a conjecture, possibly, and yet one well worth pinning a forlorn hope to, should necessity arise.
But no heroes, returning from a forlorn hope, could have had a warmer welcome from their comrades.
Miss Ingram rose solemnly: "I go first," she said, in a tone which might have befitted the leader of a forlorn hope, mounting a breach in the van of his men.
To do so meant changing a well-ordered advance into a forlorn hope.
He was moving softly to the door, when, in a forlorn hope of saying something naturally - which I never could, to this man - I said:
But if that too proves a forlorn hope, the disappointment may be offset by an announcement about enterprise zones to be set up in the North East.
Geordieland had only five finishers behind him in the Melbourne Cup last year after breaking a blood vessel, and Osborne said: "It all went wrong for him in Australia, but he put up a good performance at York last time and is not a forlorn hope for the Gold Cup.
We note the company also states profits before tax will be close to market expectations if pending rights deals are completed and retail sales increase - although this strikes us a forlorn hope.
We know it is a forlorn hope but we will give it a try.
Tour manager Phil Neale said: "Having got some play on the fourth day we were hopeful of a full day when we could still produce some interesting cricket, but when we awoke to constant rain, we knew that it was a forlorn hope.