As Thames Water continues to come under fire for pumping raw sewage into the Thames, we speak to Sustainability Director of Thames Water Richard Aylard about whether they can ever stop sewage dumping, alleged lack of investment and failures of regulation.

Sewage was released from Witney Sewage Treatment Works for 15 days around Christmas. Why does this keep happening?

Ideally, we need to deal with the problem at source – by stopping the rainwater getting into the sewers in the first place. But if you’ve got over 200 miles of sewers coming into a single works, as is the case in Witney, it’s not easy to find out where the rain is getting in and then stop it.

Most of the time it’s not happening - so if you put a CCTV camera down the sewer you don’t see anything. Equally once the pipe is absolutely full you can’t see anything because it’s under water.

So if you can’t treat the problem at source in the short term then you can build more treatment capacity. That’s why we are expanding the works, with an £8m upgrade to provide an additional 50 per cent treatment capacity. Work will start later this year for completion early 2024, but if we can manage it, possibly late 2023.

Could you ever stop the releases completely?

Absolutely, we want to get to the point when we will never have to discharge any untreated sewage, but it will take a long time and has to be done step by step. We will prioritise the work – this will include looking at the sensitivity of the river it’s going in to, so Witney would score highly because it’s going into the Colwell Brook and then the Windrush. But all of our customers pay the same bill.

Why is Witney so far behind the curve for demand when more housing is making things worse?

I’m not sure quite how far we are behind the curve. We spent around £4million on extending the works in 2003, and a further £5million in 2013, and now we’re spending £8million extending it in 2022/3 so it’s been expanding regularly to cope with growth.

It isn’t the foul flow from the new houses that causes the problem – that’s a comparatively small volume. It’s the rainfall that runs off roofs, drives and hard surfaces, what we call surface water. It’s when that flow gets into the sewer network, where it doesn’t belong, that the problems happen.

We’re wanting to work with WASP [campaigners Windrush Against Sewage Pollution] and other local organisations on putting out questionnaires, trying to get back to the proper way of doing things, which is using soakaways and surface water drainage to keep rain out of the sewers.

But for modern developments, provided they are connected up properly, with separate surface water systems, we generally have enough capacity for the foul flows.

So that is an issue for the planners?

Part of the problem is that under the current legislation developers have an automatic right to connect to our sewer network. The Government gave themselves the power to remove that automatic right but no Government in last 10 years has enacted the provisions, as they have in Wales, although it’s on the statute book.

We are working with a number of MPs to put pressure on Defra to get this enacted.

People are surprised we are not a statutory consultee on planning matters but we work well with West Oxfordshire District Council, and talk to them.

Protesters blame the pollution on a total failure to invest in infrastructure. Do you pay enormous sums to shareholders and senior executives while reducing investment?

The amount of dividends paid to external shareholders for the past four years is zero.

Thames Water is owned by a consortium of pension funds and infrastructure funds – the two biggest shareholders are the Canadian pension fund Omers and USS, the British universities pension fund. And then there are sovereign investors and a number of other pension funds – they are all long-term investors. And they’ve been able to say actually we need to sort out the performance of Thames Water so we won’t take a dividend for four years so everything can go into improving infrastructure and customer service.

We don’t pay any corporation tax basically because we are investing so much money. We’re investing over £1billion a year in infrastructure and that's what the Government wants to encourage through the tax system – this isn’t some kind of fancy Cayman Islands scheme. It’s an automatic deduction that defers tax while we are investing at the current rate.

[Total renumeration for 2020/21 for Executive Directors was £1,593,000, which includes annual bonuses totalling £538,000 - those figures can be found in the annual report.]

Thames Water has over 180 criminal convictions, was fined £20million in 2017 and £4million this year for polluting Seacourt Stream in Oxford. Does the water company treat the Environment Agency fines as business expenses?

Absolutely not. At a time when the company isn’t paying any dividends to its shareholders, or indeed at any time, having to find money for fines is a serious matter… in any case the reputational damage is at least as important as the fine.

Are the regulators failing to enforce the law against the water companies allowing them to get 'out of control'?

No, that’s not true. The companies are very well controlled by an economic regulator Ofwat, environmental regulator the Environment Agency, drinking water regulator the Drinking Water Inspectorate and by the biodiversity regulator Natural England, plus the Health and Safety Executive.

Would you like to apologise to the people of Witney and Oxfordshire who can’t take their children paddling or the wild swimmers of Oxford who missed their festive dip?

As far as we are concerned, any discharge of sewage is unacceptable. Of course we are sorry when that has an impact on local people.

What we have been doing since April is issuing live notifications, for Witney and five other sites in this area, whenever these discharges happen so people can take a sensible view for themselves about whether to go in the water or not. By the end of the year we will be doing that for all our sites.

What I would also say, and we don’t give public health advice, is that sewage is not the only hazard in rivers. So we would say whatever the conditions if you go near the water – whether you’re fishing, canoeing or swimming - be really careful about washing your hands afterwards.