Warning about electrical storms
With the reports of violent thunder storms across Northern England and the Midlands it is advisable to disconnect ADSL kit from the phone line during the storm. People may also wish to disconnect their computers since a lightning strike will often affect both the mains power and phone lines. Use of power surge protectors will afford some protection, but this is not guaranteed in cases of a direct strike.
Generally the lines most at risk are overhead ones, underground cabling is much safer, though a very close strike may still cause damage.
NOTE: Turning off the switch is not enough, you should disconnect the power and phone leads totally.