[Thanks to Thomas Brown of Cloisters for writing this case summary]
Lady Smith, sitting in the EAT in Scotland, has held in Dolphin Drilling Personnel Pte Limited v. Winks, that it is an error of law for an Employment Tribunal to apply a 'substantial connection' test when considering whether there was territorial jurisdiction to consider a complaint of unfair dismissal. Such an approach is inconsistent with the House of Lords' decision in Lawson v. Serco  ICR 250.
As a general, though not absolute rule, place of employment is decisive. Expatriate or peripatetic employees may be exceptions to that rule. Questions of 'substantial connection' are relevant when considering if an expatriate employee may present an ET complaint, but the existence of a substantial connection is not alone decisive. The circumstances of W, who was employed by a Singapore company and worked on an oil rig off Nigeria, did not support the conclusion that jurisdiction arose.