Life-buoy

The honorable member would however, appear to have been imbued with the spirit of Prophecy, for the contempt he so much dreaded, has fallen on the party to which he belonged, sinking the Tories to a depth that renders it beyond the power of the most gigantic talent to replace them in their former position, or restore the corruption and boroughmongering, so long the life-buoy of a dissolute ministry.

Source: wiktionary

Here now's the very dreaded symbol of grim death, by a mere hap, made the expressive sign of the help and hope of most endangered life. A life-buoy of a coffin!

Source: wiktionary

The life-buoy is of value just in proportion to the speed with which it can be thrown over.

Source: wiktionary

And so it was that when Lovibond received the letter from Jenny Crow, he rose to the cue it offered like a drowning man to a life-buoy.

Source: wiktionary