If it becomes a real problem, take it up with BT (or ntl for cable telephone) as I believe it is a line or exchange problem.
I live about 5 km from my exchange, so I can get 512 broadband but probably not 1 Gb. I find that very occasionally (sometimes 2 or 3 times in quick succession, then nothing for days or weeks) the adsl connection is dropped momentarily. Checking with the router shows that it is still connected to the adsl carrier, but no longer to my ISP. Rebooting cures it, though sometimes a couple of reboots are required.