My hon. Friend highlights an important point: the origin of this problem links back to the Victorian combined sewer system we have, where street drainage systems are linked into the foul water drainage system. Since the 1960s, new housing developments have been required to be on a different drainage system, but I am sorry to say that all too often they have ended up plumbed back into the sewer. One key thing that
water companies will be prioritising is, where possible, particularly on those later housing developments, ensuring that the drainage system is genuinely separated from the sewer system.