Petition Force drivers of HGV's to leave sufficient gap between them to allow cars to overtake

As a driving instructor in Norfolk & Suffolk where ther are very few Dual Carriageways and no motorways, I often encounter HGV's travelling in a line of 2 or 3 vehicles that make it very difficult to overtake. Unfortuately many of these HGV's are travelling during peak tavel times when commuters are in a hurry. This leads to frustration and tempts people to overtake in some very precarious situations. On driving test if you travel too slowly and cause inconvenience to the vehicles behind this results in a serious fault and the pupil fails the test. Knowing that HGV's have a reduced speed limit it should be mandatory that they leave a sufficient gap to allow for safe overtaking. Many of these HGV's stay close to each other to improve fuel economy by reducing wind resistance but at what cost to the rest of us road users.