Solar storms causing problems!
There's been a lot of solar activity (winds, storms, sunspot activity, solar flares, northern/southern lights and CME's) recently and this has been causing problems. The last week of February was affected by erratic download speeds varying from a 98% drop in speeds to around a 10% drop. Upload speed was more or less normal. The USA was hit particularly hard as several websites went down, along with DNS servers.
The odd thing was that other wi-fi devices were fine and connected to the internet as usual. My wired machine, however did not. On Friday 1st March I performed a speed test and the download speed is where I'd expect it to be. Another odd thing was that I was able to ping websites successfully, but I could not access them through browsers. NASA are reporting that a lot more activity is coming Earth's way on the 9th. Lets see what happens.
I also post the occasional video about this here: https://community.virginmedia.com/t5/Community-Natter/What-are-you-watching-now/td-p/2914384
More reading: solar flares and geomagnetic storms - Search (bing.com)