Busted Flush Meaning

(Britain, idiomatic) Anything which ends up worthless despite great potential.

Example:   I thought I'd draw another spade, but I ended up with a busted flush.
2004 May 2, Andrew Rawnsley, "Mission not accomplished," Guardian online (UK) (retrieved 14 Oct 2012):
  If this [Tony Blair] is such an utterly busted flush of a leader, why are so many Tories and their outriders so keen to have this Prime Minister gone before he can fight another election?