The compensation provided by the construction of a huge container handling facility on the northern edge of the Thames Estuary included a new inlet of inter-tidal mudflats just across the river on the edge of Cooling Marshes. Salt Fleet Flats Reserve as it is called was created by building a new sea wall inland of the estuary edge and then removing the old sea wall to let the sea wash in. The inter-tidal area today is full of oozing mud and well used by wigeon, teal, shelduck, curlew, dunlin and avocet, and the edges provide a sheltered high tide roost for these and a large flock of black-tailed godwits. On a sunny day in January and on a big tide, the place is an important refuge for thousands of waterbirds and a wonderful sight.

The need to compensate for major developments is enshrined in the Habitats Regulations, a law that was required to meet European environmental legislation, the so-called Habitats and Birds Directives. The legal obligation imposed is for no ‘loss of integrity’ of the Thames Estuary protected area. This means that if anybody wants to tarmac a chunk of estuary for a new container port then they have to put some estuary habitat back nearby before they start digging. It is a costly process but, because of the ingenuity of the engineered solution, highly effective. And you cannot just do this without proving the construction could not be placed somewhere else; this legal ‘test of alternatives’ was what befell the proposed port development in Southampton Water some 20 years ago, ironically in part because DP World London Gateway, as the Thames facility is called, was being planned at the same time and was for many reasons the better option. The container port at Felixstowe was also required to provide a similar area of compensatory mudflats and adjacent wetland reserve at Trimley Marshes when it expanded its footprint further into the Orwell estuary. It remains to be seen as to whether these onerous but valuable legal safeguards for the Nation’s most important protected areas will remain in place by a government now untied from the European Union and so free to reduce ‘red tape’ for developers.