THE Ministry of Defence broke environmental safety standards after a cooling water discharge at HM Naval Base Clyde, new information has revealed.

Staff at HM Naval Base Clyde did not notify the Scottish Environment Protection Agency (SEPA) in a "timely manner" over the discharge at Faslane and resulting breach of their licence, the agency says.

The details are revealed in a compliance database for all Scottish businesses which overall found that more than 90 per cent complied with environmental requirements for the fifth years in a row.

More than three quarters of almost 5,000 businesses in the database were rated as "excellent" and only 246 were "poor" - one of them being the naval base.

Their entry on the SEPA registerstates: "The site has been assessed as 'poor' due to a cooling water discharge which breached the consent level for total residual oxidants on one of the four samples collected during the year, and the operator did not notify SEPA of this breach in a timely manner."

The data comes from 2019, the latest available year after SEPA was subjected to a cyber attack in December 2020.

Read more: Royal Navy submarine crew reunited with families at Faslane

The agency will be consulting on a new way to ensure compliance in future.

Ratings are based on a business's performance compared to their licence.

The base had a "good" rating in 2014 and then "excellent" from 2015 to 2018.

The only other "poor" rating in Helensburgh and Lomond was Lomond Castle in Arden under the category of private water and waste water.

SEPA states: "Site has failed to meet requirements of licence discharge conditions."

Apart from "good" ratings in 2014 and 2016, the site has been "poor" every other year according to SEPA's website.

Read more: Capita Defence Fire and Rescue boss grilled over HMNB Clyde jobs row

All other sites across the area were rated either "excellent" or "good".

SEPA says that because of the pandemic, it was impossible for the agency's staff to properly run formal compliance checks.

Jo Green, acting chief executive of SEPA, said: “The environmental compliance of Scottish business really matters, as does the visibility of performance data.

"That’s why today we’re publishing the latest compliance assessment data recovered following a December 2020 cyber-attack by international serious and organised criminals.

“Whilst draft data was stolen, illegally published on the dark web, and subject to media reporting in October 2021, it’s important we published final data in line with our recovery strategy.

"Here we’re pleased that for the fifth year in a row, nine out of 10 Scottish businesses did the right thing by Scotland’s environment and that over seven out of ten achieved our top billing.

“We know the importance of compliance information and, as part of our recovery from Covid-19 and the significant cyber-attack, we’re committed to consulting on a new, publicly accessible compliance assessment approach in 2022.

"We remain clear that compliance with Scotland’s environmental regulations is non-negotiable, and committed to driving performance and to publicly demonstrating the progress of Scottish business.”

A Royal Navy Spokesperson said: "As part of our compliance with legislation and commitment to ensuring the safety of the public and environment at HMNB Clyde, an isolated event was reported to SEPA.   

"A higher-than-usual level of residual oxidants had been measured in a 2019 sample from the Gareloch. The levels have since been normal, are well below the levels in drinking water, and are considered not to have an adverse environmental impact.

“The Royal Navy takes its environmental responsibilities very seriously and continues to work with the relevant UK authorities to comply with legislation and reduce environmental risk.

“HMNB Clyde continues to monitor, report and work with SEPA.”

The owners of Lomond Castle have been approached for comment.