Re:Best Weed Killer
sodium chlorate is what I use (until it is banned for public sale at the end of the year). It is powererful and actually 'kills' the ground for up to six months which ensures no more weeds can grow. Caveat is that if new growing medium is inserted weeds may still appear so you should sweep the drive from time to time. Its quite cheap compared to the weedol type overpriced and undereffective stuff.
you can still get it from the likes of B&Q, big tub is about £12