gentlegreen writes
Dear URGlers,

I recently found that the water from my mum's roof was backing up and taking
an age to get down to the soakaway.

The offending tree has now been removed, but the clay drainage pipe is still
stuffed with roots.

Apart from diverting the water elsewhere and allowing the roots to dry and
shrink, I wonder how best to speed the process without major excavation.

The gunpowder option has been considered and discounted ;-)

Would Sodium chlorate or ammonium sulphamate expedite the situation ?

I presume you don't want to get a drainage company in? They can often
clear roots from inside without need for excavation, and can if required
line the pipes to help prevent re-occurrence.

Also, check buildings insurance - it may be covered under that, and if
so, getting in a drainage contractor may be the easiest option.
--
Kay