globally set \markup \box #'box-padding

[Kieren MacMillan]

[Lilypond 2.11.49]

Hello all,

I need boxed markups with a set padding, i.e. I'm currently using

    ^\markup { \override #'(box-padding . 1) \box { ... } }

How can I set this value once, rather than needing to do it each  
time? I've tried

        \override TextScript #'box-padding = #1

but Lilypond says

    "warning: cannot find property type-check for 'box-padding'..."

Any help would be appreciated.
Kieren.