ROI Land Investments Ltd. v FD
Under Article 21(1)(b)(i) and (2) of Regulation (EU) No 1215/2012, an employee may sue in the courts for the last place where or from where he or she habitually carried out his or her work a person - whether or not domiciled in a Member State - with whom the employee has no formal employment contract, if that person is directly liable to the employee under a letter of comfort that was a prerequisite for concluding the employment contract with a third party, provided there is a hierarchical relationship between that person and the employee.