Removing bush roots

[Si]

Trying t clear a space in front of the house to put some veg in. Problem is that there is an old bush there.  Have dug down and got as much out as possible but the main, thick root goes under the brick work and to make matters worse the broad band cable is mixed up with it too.  So can't really use any more excavation and brute force to get it out.  Any ideas as to what I should do next?  Leave it to regrow a bit and poison it with something - but does that mean I can't grow any veg around it until it's all gone?

[SteveC]

Not everything will regrow from a bit of root, so I'd cut out as much as I could, then plant what ever I wanted. If I saw any of the bush coming back, I'd prune it right down to the ground again (or below if possible).
Any idea what sort of bush?

[Si]

I'm afraid the best I can offer as a description is that it's a medium green one.
It has been cut back to sub surface level before and regrew.  Guess I'll just keep hacking it out and that might deplete the roots of life eventually?