Lough Neagh pollution: 80% chance of devastating outbreak happening again this year, says Minister, as UUP call for 'increased focus' on problem

That’s according to Agriculture, Environment and Rural Affairs minister Andrew Muir, who has said that although his department can’t predict how bad any outbreak of blue-green algae will be, a leading scientific body has calculated there’s an 80% probability of it happening this year.

In 2023, the lough – the largest lake in the UK and which provides 40% of Northern Ireland’s drinking water – turned green as levels of noxious algae not seen since the 1970s choked aquatic life and bird and insect populations plummeted.

Thought to be driven by fertiliser, slurry and other runoff from nearby farmland increasing bacteria levels in the lough, despite a national outcry over the incident the algae returned in 2024.

Now Mr Muir has warned that “if conditions mirror those over the past two years”, Lough Neagh is likely to see “significant” algae problems broadly on the same scale as the last two summers.

In a letter to UUP MP Robin Swann, Mr Muir states that his department’s analysis of the water indicates that “nutrient levels remain high in the lough”, meaning the “probability of [algae] blooms remains high”.

“Their frequency and extent are influenced by weather conditions and river flows, which cannot currently be accurately predicted several months in advance,” he stated. “It is therefore not possible for the department to accurately predict the severity of the bloom in the summer of 2025.

"However, AFBI (the Agri-Food and Biosciences Institute, a Stormont-connected scientific body) has ascertained the probability of a bloom occurrence at 80%.”

That has Mr Swann calling on Westminster and Stormont to jointly prioritise sorting out Lough Neagh’s pollution crisis, stating he’s “disappointed that we can expect a blue-green algae bloom this year”.

“Action needs to be taken urgently and effectively so we don’t continue to see a repeat of the two previous summers time and time again,” said the MP.

“Although the Environment Minister has published his Lough Neagh Action Plan, it is unfortunate that the research he has shared still suggests an 80% likelihood of a bloom this summer nonetheless.

“This plan must remain on track and delivered on time, and I will continue to seek updates from the minister on its progress. I urge him to look at every possible opportunity and resource available to protect our lough.”

Ulster Unionist MLA Robbie Butler, chair of Stormont’s Agriculture, Environment and Rural Affairs Committee, says that during a recent meeting department officials were unable to give him “a clear answer” on whether algae would strike Lough Neagh again, or how severe it could be.

“I’m pleased the minister has been able to provide more detail,” he said, “but I would have expected a greater degree of clarity by now, three years into this crisis and with the monitoring that is in place, so that we can properly anticipate the scale of any blooms and prepare for any impact on bathing and drinking water.

"Lough Neagh needs to remain a political priority, and it will certainly remain one for our committee.”