“We have once more become aware of fraudulent activity via email and internet by criminals who make use of the Vroon name to contact seafarers with fictitious job opportunities,” it said.

It asked potential employees to contract the company if they are suspicious of any such activity.

Vroon said criminals use mobile telephone numbers and non-company email accounts, such as gmail.

They attempt to obtain money from seafarers for UK or EU visa or other travel clearance.

Vroon