Strange ADSL / Phone Problem

[Desmo]

A couple of days ago our rock solid 7000+Kbps ADSL line dropped right down to 160Kbps :/

I left it thinking it would climb back up (being ADSL Max) but it didn't. So, whilst we were away yesterday, I left the router unplugged for the day and night and put it back in this morning. We're now sitting at around 3,500Kbps connection.

Sinead went to use the phone earlier only to find we have no dial tone. So, the ADSL is working (albeit poorly) but the phone doesn't work at all. This has got me confused as surely if the phone line doesn't work then it's highly unlikely that the ADSL would.

I'm going to bring a normal phone home from work tomorrow to test it as we currently use a cordless phone so I can get that out of the way and tested. After that, I guess I'll be on the blower to BT to get the line tested. Unless you guys can think of anything else?