Case T-68/15: Judgment of the General Court of 19 September 2018 — HH Ferries and Others v Commission (State aid — Aid in favour of the Øresund road-rail fixed link — Public financing granted by the Swedish State and the Danish State to the Fixed Link infrastructure project across the Øresund — State guarantees — Tax aid — Decision not to raise any objection — Decision that there was no State aid — Action for annulment — Challengeable act — Admissibility — Failure to initiate the formal investigation procedure — Serious difficulties — Concept of ‘aid scheme’ — Aid to promote the execution of an important project of common European interest — Assessment of the aid element in a guarantee — Whether the aid contained in a guarantee is limited — Proportionality — Legitimate expectations)