Warning over post-Brexit business standards
Britain's standards body is calling on ministers to commit to staying in the European regime that sets industry-wide business standards after Brexit.
The BSI said if the UK did not act it could lose its say on how rules are set in areas such as packaging and safety.
Some manufacturers fear rules could be changed to make it harder for UK firms to compete when they export to Europe.
The government said it wanted European standards to support a competitive business environment.
Without a clear commitment to two Europe-wide standards bodies - called the European Committee for Standardisation (CEN) and the European Committee for Electrotechnical Standardisation (CENELEC) - BSI believes the UK could be forced out of them.
But staying in the system would force the UK to adopt European standards after Brexit.
As one of 34 members of CEN and CENELEC, the UK adopts all their standards on products ranging from electrical goods and cables to fire blankets and alarms.
Such standards are used across the European single market and further afield, but the two bodies are private associations and not part of the European Union.
BSI director of standards Scott Steedman told the Today Programme "some certainty" was needed as Britain could lose influence over half of the standards used in the UK.
He said the British market could be fragmented if new models of regulation were introduced.
"We would lose our place at that international table for shaping international best practice," he said.
While some manufacturers are concerned that European rules could be changed to make it harder for British firms to compete in Europe, accepting the European rule book could make it more difficult to get good trade deals elsewhere.
The US, for example, dislikes the European standards system.
European rules could prevent British businesses from seeking a competitive advantage with a new standards regime of its own.
Neither CEN nor CENELEC are run by the EU, but they get about a fifth of their funding from the European Commission and just under a third of their standards support EU legislation.
They have other members outside the EU, such as Switzerland, but their work helps underpin the single market, ensuring manufacturers can easily sell goods across borders.
The director general of CEN and CENELEC, Elena Santiago Cid, told Today: "What is very important is that the UK member continues respecting their CEN and CENELEC rules that ensure there is a single standards model to get access to the EU and the UK market."
BSI - the body that used to be known as the British Standards Institution - manages the UK's membership of CEN and CENELEC.
But in practical terms the British government's decisions will dictate whether the UK can stay in the bodies.
If the UK refused to adopt European standards, or set new standards in conflict with the European ones, it would have to leave.
The government said it "wants to ensure that our future relationship with the European Standards Organisations continues to support a productive, open and competitive business environment in the UK".
Different standards are set at global, European and nation-state levels.
They are voluntary - in any particular area a nation accepts the shared international standards and agrees to abandon its own.
Businesses that do not comply with standards will find it difficult to sell and their goods. Some standards are then backed by regulations enforced by the likes of trading standards officers.