Water Industry (Financial Assistance) Bill

That is absolutely right; it is a sticking plaster approach. I have reservations about the tunnel, which I shall come on to, but I am making the case that the tunnel is the only sensible solution thought of so far because many alternatives have been put forward but they are simply not sustainable. SUDS—sustainable drainage systems—are one alternative. There is nothing wrong with them. They reduce the amount of surface run-off blowing into the sewerage system and complement other measures. However, the Government policy statement makes it clear that to prevent rain water and run-off entering sewerage systems completely will require either a new system designed to meet the principles of SUDS and source control or a completely new conventional separate water system, which would be disproportionately expensive. Although it can be installed effectively in new developments, trying to retrofit all London's properties to the required level is simply impractical. It is impractical, too, to create extra capacity in the existing sewerage system. Existing sewers cannot be enlarged or duplicated because the system is so large and complex and has so many cross-connections that most of the network would need to be enlarged to prevent CSOs from discharging. The Government's report says that substantial duplication and enlargement to most of the sewers would entail massive construction work throughout inner London, enormous disruption and extremely high costs. Converting a combined drainage system into a separate drainage system would involve the provision of a completely new network of sewers approximately 12,000 km in length. Every existing property would require connecting to the new system and the cost and disruption would be high and might lead to a large number of misconnections, which could create a legacy of problems. Any of those alternatives, if they were sustainable, would cost many times the cost of the tunnel—whether it be a SUD system or a separate rain water and sewerage system. What the opponents of the tunnel have been left with—I am sorry to see that the right hon. Member for Bermondsey and Old Southwark (Simon Hughes) appears to have joined them—is the idea of a shorter tunnel. This is a tunnel that would cover just west London—the so-called Selborne tunnel, named after the author of the report sponsored by Hammersmith and Fulham council. The shorter tunnel has none of the advantages of the longer tunnel and brings many more problems. It would effectively mean sewage stuck in the shorter tunnel for up to two weeks at a time while it became septic and could go nowhere—clearly it can flow only through the existing network of sewers in east London as capacity becomes available there. It would also require far more storage on land in west London. Thames Water's response to the Selborne report—I have no brief for Thames Water—was quite devastating, pointing out its follies and fallacies. Indeed, if we read the Selborne report, we find that it does not talk about the shorter tunnel because it was realised that it was not a workable proposition. It would cover only half of the CSOs in London—that is, it would do only half the job. East of Battersea, sewage would continue to go into the Thames; west of Battersea, including in my constituency, the tunnel would regularly be full of sewage, with all the attendant problems of smell and disease that that can cause.