Frequent dropped broadband connections

[#1]

My broadband has worked perfectly for over a year - and then suddenly in the last week frequent dropped connections for a minute or so and then normal service resumed for another hour (or just a few minutes). Often I get a new IP address allocated when this happens.

My phone line is working fine with a clear line. When I log into the Technicolor TG582n modem (which I use in modem mode) the event log shows constant drops. If I carry out a connectivity check from the modem it shows everything OK except for an error "No ATM activity detected on your DSL line."
Is this likely to be an exchange fault or on my premises? Anything more I can check? I've obviously tried rebooting the modem and router but it made no difference.

[#2]

It's worth running through the troubleshooting guides: http://www.plus.net/support/broadband/bbfaults/
I can see you've started reporting a fault, if the guides don't help then please finish reporting the fault at https://faults.plus.net
Your line is disconnecting a lot more than we'd like to see:

Is there any noise on the phone line? Dial 17070 and go for the quiet line test option.

[#3]

Thanks Chris for the chart.
That does correlate with the disconnections - up to 18 a day now, so I've raised a ticket. The phone line test shows no noise on the line and phone usage does not cause disconnections.
My modem stats are:
Uptime: 0 days, 0:15:28
DSL Type: ITU-T G.992.5
Bandwidth (Up/Down) [kbps/kbps]: 1,235 / 18,079
Data Transferred (Sent/Received) [GB/GB]: 7.85 / 29.53
Output Power (Up/Down) [dBm]: 12.8 / 0.0
Line Attenuation (Up/Down) [dB]: 11.3 / 21.0
SN Margin (Up/Down) [dB]: 5.8 / 4.3
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / IFTN
Loss of Framing (Local/Remote): 323 / 0
Loss of Signal (Local/Remote): 101 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): -
Error Seconds (Local/Remote): 31,475 / 0
FEC Errors (Up/Down): 0 / 1,978,108
CRC Errors (Up/Down): 0 / 22
HEC Errors (Up/Down): 0 / 628