Heinz wrote on Aug 11
th, 2006 at 8:12pm:
Use 1899 then. 3p per call to any UK 01 or 02 number regardless of duration.
But how are such calls routed? Often they are sent half way round the world. With voice calls you can hardly tell, but an internet connection is likely to be unreliable or even not work at all - at least that's my experience of trying to use dial-up via a prefix (in my case I was trying to dial an 0845 number more cheaply during the daytime).
If you know a technically-minded person with broadband, perhaps you could persuade them to set up a modem to accept incoming calls. Then you phone them to use the internet! The impact on their broadband speed would be negligible, but the disadvantage is their phoneline would be tied up!
Ultimately, if you are going to be online for a significant length of time during the day, you should get broadband, or at least subscribe to an 0800 ISP.