Really weird - annoying more than anything as I'd expect 'good' speeds pretty much in any major city in the UK these days but was in Worthing today and it was as bad!
I restarted the phone and it's back to 4Mbps and 1.5Mbps up/down respectively which is rubbish - it's never gone above that for me and yet the twitter T-Mobile people said there's no cap on my line "apparently" :/
I thought it was reasonably common that T-Mobile cap to 4 Mbps, though no idea about upload speeds?