The positive impact of a reduction in marine insurance capacity in the Lloyd’s of London market over the past year could be reversed if two former Catlin Group executives are successful in a $3bn ­project.

The Lloyd’s profit drive has ­already seen $100m to $150m of ­capacity withdrawn from the ­marine market.

This has been viewed as a positive factor, contributing towards a moderate hardening of hull rates, which have hit rock bottom in the past year.