Photo: Thames Anglers' Conservancy

A few weeks after the "massive" pollution incident which killed thousands of fish and insects (including protected species), the clean-up of the River Crane is near complete and there are signs that the water quality is returning to normal. Alex Chown, from the Environment Agency (EA), told FF&FT: "There are one or two back-waters where the pollution can still be observed. We are working with Thames Water is devising how best to bring about a recovery. There are few signs of pollution remaining along the majority of the river. However, anyone working on the river, or within the river is still advised to take extra precautions in case there is still an increased bacteriological risk."

On the afternoon of October 29, a two-metre valve in a major sewer serving Heathrow Airport jammed shut at Cranford Bridge on the A4 while engineers carried out routine maintenance. Initial attempts to re-open the valve were unsuccessful but, using custom-made hydraulic lifting equipment overnight, Thames Water engineers were able to force open the jammed shutter on the Monday morning. Thames Water took a lot of backed-up sewage away in tanker lorries for treatment and enlarge a contingency pipe to bypass the problematic shutter, the volume of sewage was such that the company wasn't able to tanker all of it. After the incident the river was said by anglers and wildlife enthusiasts to be "dead".

When asked by FF&FT if current legislation (i.e. the Environmental Liability Directive [ELD] 2004/35/EC which ensures polluters pay not only a fine for an incident but to also foot the bill for reinstatement of a damaged habitat back to what it was when the incident occurred), Mr Chown said: "We have an active investigation ongoing which will look into all potential offences and enforcement options. We cannot at this point in time comment on the above interpretation with regard to the River Crane pollution incident.

"During the pollution incident, the river quality had effectively no oxygen and high ammonia. The few rainfall events in November, have helped bring about some improvement by the dilution and natural flushing of the river. "It is difficult to say how quickly the river will recover but it is likely to take many years."