Broadband green light flashing - no internet access.

[#1]

Well normally all the lights are green permanently on my wireless router, but for a few days I've been having problems - the broadband light keeps flashing, and the internet one doesn't turn on.
I'm using an unsecured network at the moment,
since my plus net isn't working
Help ?

[#2]

you need to ring the faults line first 01142965188

[#3]

Hiya,  as well as ringing the faults team, to raise a fault....  as this has only just started happening, has anything changed in your setup such as adding phone extensions, using a cordless phone. 
If you pick up the phone, have you got audible noise, such as hissing, popping or crackling?
Also as the faults teams will ask this anyhow, have you tried just the router in the test socket, by removing the front faceplate, and connecting just the router via a filter?
If you do have alot of noise on the line, contact your phone provider first, and log a fault on your phone line side, and DO NOT mention you have broadband...