Mark Spencer told MPs that scientists are “ready to jump into action at great speed” to try to establish the facts if a repeat mass die-off of marine life occurs on the coastline from Hartlepool to Whitby.

Mr Spencer stressed he hopes a repeat does not happen but added “we may never find the cause” of the original incident between October and December 2021, which saw crustaceans washed ashore and dying creatures “twitching” and displaying lethargic behaviour.

Shadow Environment Minister Daniel Zeichner suggested the Government is trying to brush the issue “under the carpet”.

Research by academics, backed by the fishing industry, had suggested the incident could have been caused by industrial pollutant pyridine, possibly from dredging in the mouth of the River Tees to maintain channels for port traffic.

Teesside is home to one of the Government-backed freeports – special economic zones offering tax breaks and lower tariffs. There have been calls for a halt to dredging for the new freeport pending a full analysis of the situation.

But an independent panel last week concluded it is “exceptionally unlikely” the deaths were caused by dredging to expand a port in Teesside.

Instead, the panel concluded it was “about as likely as not” that a pathogen new to UK waters – a potential disease or parasite – caused the crab deaths.

Mr Spencer, when asked by Labour MP Kevan Jones (North Durham) about the next steps, told the House of Commons: “It is about taking advice from those scientists and working with them so they can establish the facts of what has caused this disease.

“As much as the House and I want to find the actual cause of this die-off, we have to face the scientific fact that we may never know, if that event doesn’t repeat itself, which I sincerely hope it doesn’t, we may never find the cause of that event.

“But if it is repeated then those scientists are ready to jump into action at great speed to try and establish the facts.”

An earlier investigation into the incident, led by the Department for Environment, Food & Rural Affairs (Defra), had pointed the finger at an algal bloom as the likely cause.

However, the new report also found this was “unlikely”.

For Labour, Mr Zeichner said mass deaths of crustaceans are now “regular” in the area, adding: “Why is it that 15 months on they still don’t know? Is it because we have a Conservative Government and a Conservative Tees Valley mayor who have been missing in action?

“Is it because they aren’t interested in uncovering the reasons behind it and are more concerned with trying to brush this issue under the carpet?”

Mr Spencer replied: “I think that is absolutely outrageous, to be honest, to try and play politics with this disaster. And it is a disaster. There is a shared desire across this House to try and find out what caused this die-off. It has been catastrophic to that industry.”

Cause of mass crab deaths off Yorkshire coast may never be known, says Minister