Are there any known slowdowns on the WWW at the moment ?
No such thing as slowdown on the WWW.
It's either
(a) contention/packet shaping / rate limiting at your ISP or your home setup is broken somehow
(b) DDoS or other against the website you are trying to visit
(c) DDoS againt Root DNS / other key infrastructure
99.9999% of the time, it's going to be (a).
00.0001% of the time, it's going to be (b).
(c) is highly unlikely, there's so much resilience and redundancy at that level.
So, having carefully checked your home network, next step would be to have good talk to your ISP. Also check sites such as ADSLGuide (aka thinkbroadband) for moans from other users of the same ISP.