Don't think BT are deliberately sabotaging other ISP's. They can't even provide a decent service to their own subscribers. I ditched them two months ago after their 'service' dropped to levels where it was quicker to send a letter than an email and their web access is a joke. Unfortunately the telecom system in this country is so outdated it will in its current form never provide the level of internet access our transatlantic cousins enjoy. Probably due to the fact it is run by one huge ex nationalised company whose only concern is dividends for shareholders, profits and obscene salaries for the board.
Rant over....
On a positive note I joined ezesurf's surfsaver two months ago and apart from it not being easy to sign up have been very pleased. Web access is fast and reliable, download speeds are nearly four times what I was getting from BTInternet and its 24/7 freecall access.
Happy Surfing