Whichever way you dial it?
The bit before the first space is the STD code. You don't need to dial it if it's the same as yours. If your number is 020 7890 1234 and you want to dial 020 3456 7890, you can dial either 3456 7890 or 020 3456 7890.

If you think your number is 0208 901 2345 and you think your friend's is 0208 765 4321, ringing 765 4321 isn't going to get you very far.
(Vice Admiral Sir Charles Cockbrush KCB MBE DSO, who is finding it increasingly difficult to log into b3ta.com wants to duck your aunt and kick your puppy, Fri 4 Sep 2009, 23:48, Reply)