No one likes a left lane blocker. These are the drivers who inhabit the left hand lane on multiple laned roadway and are oblivious to the traffic behind them that want to pass by. Clearly, they believe that if they are travelling at or close to the speed limit, there is no need for them to move over to the right hand lane for others.
If you are driving in the left hand lane and you are driving at a speed less than normal speed of traffic at the time and place and under the conditions then existing, you must drive in the right hand lane if it is practical to do so. It is important to note that the words speed limit do not appear anywhere in the last sentence. If you are slower, move over. If you choose not to, you are at risk of being ticketed for failing to keep to the right unless it is unreasonable to do so.
There are two exemptions to this rule. The first allows you to move into the left lane to pass someone travelling slower than you are and the second allows you to use the left lane to prepare for a left turn at an intersection or into a driveway or private road. Preparation for the left turn will depend on the traffic volume at the time, but it is unlikely that a kilometer or more will be considered acceptable.
Left lane blockers increase the risk caused by aggressive drivers. The aggressive driver cares for no one but themselves and will try to get by using any means available. By refusing to move over, the left lane blocker contributes to unsafe lane changes and tailgating behaviour. A defensive driver will reduce the risk by giving right of way even when the law does not require them to.
Driver on right - Section 150(2) MVA