Uncleared litter

There is a large amount of uncleared litter on the verges along the stretch of the A1M that I regularly travel on. That is between the marked point near Junction 6 and Junction, the M25 junction. This litter continues on the M25 between Junction 23 and 25. Apart from the litter clearly thrown from motor vehicles there are discarded tyres. I have particularly noticed this litter over the last few months. What is the schedule for clearing litter on the motorways? The longer it is left it will encourage more drivers and passengers to discard litter. I think it would be a good idea to close a stretch of motorway regularly to clear litter, and publicise the reason for the closure. This might make people think before littering our roads.