Just to add to VHG's post:
The broadband speed available to you is linked to the 'contention ratio' used by your ISP.
Budget ISPs typically use a contention ratio of 50:1, which means that up to 50 users share a connection to the internet at the exchange. If you're the only one of them using the internet (say at 3am) you'll get a fast speed; if everyone else is using the internet as well (e.g. in the early evening and particularly if they're all using things like Youtube or iPlayer) you'll get a much lower speed.
Better contention ratios are available by using ISPs that mainly serve businesses, rather than domestic customers. However they come at a higher price. (My ISP uses contention ratios of between 12:1 and 8:1, and I get 'ADSL2+', which effectively gives me two connections at the exchange as well - thus giving me twice the speed that my neighbours get. However I pay over £18 per month for that service, without any 'add-ons' such as telephone calls or TV services).
If you want a connection at the exchange all to yourself, it's certainly possible. (Many businesses choose that option). However you'll have to pay at least £200 per month, and possibly much more.
As with much in life, you get what you pay for!