Cover (envelope) fr. with 1d+2d+1S (SG 42+45+73) tied by "SW16" barred cds and canc. LONDON SW*22.AP.61" to Athens (Poste Restante). Oval "PD" in red, transit postmarks "ANG. AMB. CALAIS*23.AVRIL.61" and "PARIS*23.AVRIL.61", arr. "ΑΘΗΝΑΙ*20.ΑΠΡ.61" (type III). Flap on reverse miscut but complete. 1S stamp defective. Fine and scarce.