I have an intermittent fault with landline. Sometimes it works/there is a dialling tone and sometimes there isn't. I can sometimes make calls and sometimes I can't.
Incoming calls also intermittent and sometimes go straight to anserphone without ringing.
An engineer came out once before a few weeks ago but because it was working at that time, there wasn't much he could test. He found a loose bit of wire in the box on the wall which he thought might be interrupting connection.