The UK Government is reviewing its membership of a controversial pact over claims it is at odds with international climate commitments.
Westminster has called for the Energy Charter Treaty to be “modernised”, warning that it would be considering withdrawal if it is not.
It follows a similar move by the European Union last month.
The treaty has historically provided protections for investors in fossil fuels, but critics say it offers oil and gas firms an avenue for massive legal claims.
In a statement the UK Government’s said the country’s future membership will depend on whether proposals for the treaty’s modernisation are adopted in November.
A major agreement to bring the pact up to speed – by maintaining current benefits while supporting the transition – was agreed last year.
These changes, which focussed on CCS, hydrogen and other renewable sources, were supposed to be adopted in November last year.
But several EU member states have decided to leave the treaty, leading to an impasse on modernisation.
Graham Stuart, the UK’s energy security and net zero minister, said: “Rather than being stuck indefinitely with an outdated treaty, the UK wants to see an agreement on a modernised treaty as quickly as possible.
“In its current form, the Energy Charter Treaty will not support those countries looking to make the transition to cleaner, cheaper energy sources such as renewables – and could even penalise our country for being at the forefront of those efforts.
“Countries around the world will be looking to boost their home-grown energy sources, including with new clean technologies – the Energy Charter Treaty therefore must be modernised. That’s why we will be reviewing our membership, and considering withdrawal if that vital modernisation is not agreed.
“The UK will continue to carefully consider the views of stakeholders in business, civil society and Parliament to inform the UK’s approach. The UK’s strong rule of law means it remains an attractive destination for investment in the energy sector regardless of its Energy Charter Treaty membership.”