Hairpin confusion

[Mark Probert]

Hi.

I'm wanting the hairpin to terminate at the end of the whole note, yet 
this is not what is happening (it only appears under the 8th note). 
What is the correct way to make go the full duration?

TIA 

 .. mark.

---
\version "2.22"

tune = \relative c'' {
  \clef treble
  r2 r4 f8 a\<~ | a1\! |
}
\score {
  <<
    \new Staff \tune
  >>
}