Arbitration — Arbitrators — Appointment — Arbitration clause submitting disputes to International Centre for the Settlement of Investment Disputes (“ICSID”) contained in investment agreements — Arbitrators to be appointed by parties — State refusing to appoint arbitrator — Procedure in default of party appointment

Arbitration — Jurisdiction — Agreement to arbitrate — Requirement of written consent — Arbitration clause submitting disputes to ICSID contained in agreements — Whether sufficient written consent — Dispute regarding jurisdiction — Competence of tribunal to determine jurisdiction — Unilateral notification by State of intention to exclude type of dispute from ICSID jurisdiction — Whether notification effective in relation to prior agreement — Jurisdiction of tribunal in respect of legal disputes arising from investment — Meaning of “investment”

Arbitration — Procedure — Procedure to be followed in default of appearance by party — Jurisdictional issue — Determination as preliminary question