Flood defences – Classification – Defendant classifying sluice gates on Manchester Ship Canal as formal flood defences falling to be disregarded when assessing flood risk and designating flood zones – Whether misapplying own policy – Claim allowed
The Manchester Ship Canal was vested by statute in the first claimant, whose sister company, the second claimant, owned 300 acres of development land in the vicinity of the canal. The canal provided a 36-mile long navigable route for sea-going vessels from the estuary of the river Mersey to the centre of Manchester. The water level was regulated by several sets of sluice gates, which allowed ships to pass along the canal via ship locks. The sluice gates automatically adjusted up and down, in response to water sensors, to control the flow of water on a continuous basis and could also be adjusted manually. All sluices could opened in potential flood conditions.
In December 2010, the defendant decided to classify the sluices on the canal as formal flood defences when producing flood maps and designating flood zones, such that, under government policy guidance in PPS25 and the defendant’s own policies, they fell to be disregarded when assessing flood risk. The defendant took the view that flood risk should therefore be assessed on the hypothetical assumption that the sluices had failed when in a closed position, preventing water from passing along the canal. As a result, land adjacent to the canal, including land owned by the claimants, was designated as flood zone 3a, with a high probability of flooding, instead of flood zone 2, with medium probability. That designation adversely affected the value of the land since it affected the ability of local planning authorities to allocate it for development.
The claimant applied for judicial review of the defendant’s decision. Its primary contention was that, in classifying the sluices as formal flood defences and basing its flood zone assessments on the assumption that the sluices would fail and remain closed, the defendant had misinterpreted and misapplied its own relevant policies.
Held: The claim was allowed.
The term “flood defences” in PPS25 was intended to refer to structures the purpose of which was to protect against flooding. It was not intended to refer to structures that had a different function, even though they might also assist in flood protection. The defendant had interpreted the term in a similar way in its own policies. It had maintained a distinction between formal flood defences, for which flood defence was the primary function, and “de facto” defences that provided a flood defence function although that was a secondary or indirect purpose. It was relevant that certain policies specifically stated that sluices controlling normal water levels would not be mapped as flood defences. Moreover, none of the relevant policies listed sluices among the formal defences that were to be disregarded.
In drawing up its policies, the defendant was intending to define and categorise, as best it could, those structures that were or were not to be treated as “formal” or “de facto” flood defences, in order to give clear guidance and achieve consistency in flood mapping across the country. Since flood zoning could have a drastic impact on future development, it was appropriate that both PPS25 and the defendant’s own policies were careful to limit the extent of the flood defences that were to be disregarded when mapping flood zones. Both were required, by EU law, to apply the precautionary principle in a proportionate way to strike a balance between risk avoidance on the one hand and economic development on the other.
Where the defendant had stated, as a matter of policy, that a particular type of structure would not be treated as a formal defence, it had already exercised its judgment in respect of the structure in question and incorporated that judgment in the policy. It could not lawfully depart from its own policy without a legitimate reason: Nadarajah v Secretary of State for the Home Department [2005] EWCA Civ 1363 applied. On the evidence, the sluices had been designed, and had since been maintained, to control the water levels along the canal so as to enable safe navigation of sea-going vessels along the canal. Since they also made a valuable contribution to flood reduction, because of the continuous regulation of water levels, they could properly be described as “de facto” flood defences in accordance with the defendant’s policy. However, they could not properly come within the description of “formal” flood defences. The defendant had given inadequate consideration to the distinction between formal and de facto defences. It had thereby failed properly to interpret, apply or have regard to its own policy and its decision should be quashed.
Peter Village QC and Stephen Whale (instructed by Clyde & Co, of Manchester) appeared for the claimant; Gordon Nardell QC and Christiaan Zwart (instructed by the legal department of the Environment Agency) appeared for the defendant.
Sally Dobson, barrister
