As a long time ATC, and pilot, (more than 30 years for both) I have heard all the arguements about whether or not an aircraft should land, at pilots discretion, without a landing clearance. Despite what Binoculars states quote 'But in a CAVOK situation where an RPT jet is aware of all tower conversations' - sorry, that may apply where there is a single runway and ground control/aerodrome control is carried out on the same frequency - but it cannot possibly apply where you have, for example, parallel runways and multiple taxiways, and several Tower operating frequencies. A radio failure in the Tower may be the reason that no clearance is issued - and keep in mind that the controller may, for various reasons not obvious to the pilot, have been about to issue go round instructions. In my experience there have been occasions when a landing without a clearance would have been uneventful and consistent with the controllers intentions if the instruction could have been issued. However, as several contributors have identified there have been other occasions when the circumstances were such, and could not have been apparent to the pilot, that proceeding with such a landing would have had serious consequences. I'm with those who vote for the landing clearance option. Please don't respond with tales about landing clearances being received while vehicles/workers/aeroplanes/childrens pets etc were occupying the runway at the time. Everyone is entitled to make a mistake - but we do worry about the repeat offenders.