Like some others I protect my mobile number and only divulge it to friends or when forced for some reason. RBS still haven't won their very long winded and sometimes quite threatening campaign to get it from me ,though.Hence I rarely get cold calls on it.
I have a landline because
a) if I forget to charge my mobile , or can't find it (!) then the landline is there.
b) I have a landline phone which intercepts numbers not in my 'phonebook' and I can choose whether or not to accept the calls. So I never have to answer cold calls on it either.
Landline and 4g broadband cost around £28 pm, mobile ( SIM card only) is about £8pm
My garden has been ruined by ????



