NTL ex-directory no. What code so my number shows?

Question

I have an ntl phone line and number which is ex-directory. I'm trying to call a number but it does not accept withheld numbers. Does anyone know the code I dial before the number, so that my number shows up on their end? thanks :)

Thanks for the helpful advice. I HATE phoning them as it takes fifteen mins to get through to any human and then its inevitably the wrong dept, they "transfer" me and cut me off. I'll see if anyone here knows the code first lol

Answer 1

not everyone knows this but if you dial 151 instead of the premium rate line its free x

Answer 2

Better off calling ntl "customer service" if you have a day free.