Shipping regulators admit that serious safety questions need to be answered in the 22 months before the global 0.5% limit on the sulphur content of fuel comes into force.

When IMO delegates sat down in London this month to discuss the 2020 introduction of the new limit, talks focused on port state and flag state policing and enforcement.

The thrust of the discussion centred around deterring non-compliance and creating a level playing field for commercial competition.