Unjust enrichment and SPVs: The building contractor in this case had entered into a building contract with an SPV (Special Purpose Vehicle company). This SPV had no assets of its own and the sole shareholders were Mr and Mrs Costello. When the SPV defaulted on payment the contractor sought restitution from the Costellos on the grounds of unfair enrichment (as the Costellos had benefitted from the contractor's works as owners of the land and should therefore pay). The contractor's claim was rejected. The contractor had voluntarily contracted with the SPV, not the Costellos, and had therefore accepted the risks of the SPV not being able to pay. The contractor could have protected itself by asking for a guarantee from the Costellos. This case highlights the importance to contractors to carry out due diligence on their employers and ask for a guarantee if necessary.