Millennium, a specialist marine and specie underwriter at Lloyds, is one of a number of insurers who face paying out for the £52m worth of diamonds stolen from a Dutch airport last Friday. The heist is reported to be one of the biggest in history.

Responsibility for the gems, which were stolen from an armoured security van in Schiphol airport near Amsterdam, is understood to rest with security logistics firms: Brinks, Ferrari International and Malca-Amit.

Millennium confirmed it is the lead underwriter for Brinks. Willis is believed to be the broker.

A source at Lloyds said that the robbery would have a serious impact on the whole specie sector, with several specie insurers believed to be liable to some degree.

Up to £620,000 of loose Arges diamonds came from London-based gem specialist Cool Diamonds. Proprietor Michael Einhorn told Insurance Times that his cargo was fully covered, as it had already passed through customs. Willis was unavailable for comment.