allowing postcodes without a space (as well as with a space)

Hi Guys,
 
I have this validation script that checks the postcode. At the moment however it does not allow a user to enter the postcode without a space in it.
(GIR 0AA|[A-PR-UWYZa-pr-uwyz]([0-9]{1,2}|([A-HK-Ya-hk-y][0-9]|[A-HK-Ya-hk-y][0-9]([0-9]|[ABEHMNPRV-Yabehmnprv-y]))|[0-9][A-HJKS-UWa-hjks-uw]) [0-9][ABD-HJLNP-UW-Zabd-hjlnp-uw-z]{2})
 
Thanks

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