An important international agreement protecting the marine environment from pollution by alien species, will come into force next year despite the UK not signing it.

In the last 12 years every country around the North Sea ratified the International Maritime Organisation’s (IMO) new convention on ballast water control, apart from Britain.

However Finland has now signed, ensuring it will become law which will apply to UK shipping, regardless of the government’s position.

The issue was highlighted recently by the community campaign group Cromarty Rising. It is fighting plans to transfer nearly nine million tonnes of crude oil between tankers at anchor, in the environmentally precious waters at the mouth of the Cromarty Firth.

Harmful non-native species, bacteria and pathogens can be carried by the likes tankers from the other side of the world in untreated ballast water, which they then discharge approaching port.

It has been calculated that there are 45,000 cargo ships moving more than 10 billion tons of ballast water around the world each year, providing plenty opportunity for hitchhiking species.

Some such as the North American comb jelly, Zebra mussel and North Pacific seastar; have had an enormous environmental and economic impact in the Black Sea, the Great Lakes of North America and Southern Australia respectively.

Currently IMO rules only state that a ship should change ballast water during its journey.

Under the new IMO convention ships “will be required to manage their ballast water to remove, render harmless, or avoid the uptake or discharge of aquatic organisms and pathogens within ballast water and sediments.”

Countries have been ratifying the new convention since 2004 including France, Germany, the Netherlands, Belgium, Denmark and Norway. It required 30 IMO Member States, representing 35 per cent of the world shipping tonnage to sign for it the become law. The UK’s signature would have been sufficient this year, but we still didn’t sign.

However Finland did earlier this month which IMO Secretary-General Kitack Lim, described as “a truly significant milestone for the health of our planet.”

“The spread of invasive species has been recognized as one of the greatest threats to the ecological and the economic well-being of the planet. These species are causing enormous damage to biodiversity and the valuable natural riches of the earth upon which we depend. Invasive species also cause direct and indirect health effects and the damage to the environment is often irreversible”

The UK’s position is confusing. The Maritime and Coastguard Agency, for the UK Government’s Department for Transport, said ministers welcomed the ratification by Finland, adding:

“During this crucial time the UK Government will continue to play a leading role at the IMO to ensure the smooth, efficient and robust implementation" of the convention.

It is difficult to understand how refusing to it for 12 years, unlike all around us, constitutes a leading role.

Indeed Dr Richard Dixon, Director of Friends of the Earth Scotland found it "a bit embarrassing" that this welcome measure would be implemented "despite the UK rather than because of us."