Global shipping firm Clarksons has warned that confidential data stolen as a result of a "cybersecurity incident" could be made public, following the company's refusal to pay a ransom to hackers.

In a statement, the shipbroker, one of the largest in its sector, said that it had fallen victim to a "criminal attack" in which attackers gained unauthorised access to the company's computer systems via the use of a "single and isolated user account" which Clarksons has since disabled.