The issue threatens to scupper the ministerial meeting, in Paris, aimed at reaching an agreement to limit industrial pollution in the north-east Atlantic.
Britain is refusing to sign unless the other 11 countries agree a compromise allowing the UK the option to dump intermediate and low-level radioactive waste after a 10-year moratorium.
The meeting should end today, when ministers hope to sign the new treaty. If any country refuses to sign, the treaty cannot come into force.
The new convention should update and merge two 20-year-old agreements - the Oslo and Paris conventions - limiting marine dumping of waste containing heavy metals and industrial chemicals that persist in the environment.
The Government says it is not dumping nuclear waste at present, but wants to keep the right to do so should it decide that this is the most environmentally acceptable means of disposing of bulky items such as decommissioned nuclear submarines and power stations.Reuse content