Removing spaces from phone numbers..?

Hi there, can any body help me - I need to find a formula for stripping out gaps in phone numbers.... eg for changing 07879 813 359 to 07879813359. It doesnt matter if I lose leading zero, but I definitely need to lose the gaps!

I am sorry I haven't been able to work this out, but if one of you lovely people can spot how to do it I'd love to hear from you!

Cazz x

=SUBSTITUTE(A1," ","")

Richard

thanks so much, that's brilliant!!!!!

Cazz x