The Highways Agency is an Executive Agency of the Department for Transport (DfT), and is responsible for operating, maintaining and improving the strategic road network in England on behalf of the Secretary of State for Transport.
Highways Agency web site
Guidance for work on hard shoulders and verges (see P(6) on page 7 for reference to litter picking)
Highways Agency Annual report 2009/2010 This 85 page document use the words “litter” and “cleaning” just once
Highways Agency Business Plan of 30/03/2011 makes no reference whatsoever to “litter” or “cleaning”
National Road Users Satisfaction Survey Those surveyed were asked asked( see page 52) to evaluate the following statement regarding motorways “The road is kept free from litter” . This could be construed as only referring to the road surface and not the adjacent verge.
Road worker safety strategy Lane blocking vehicles seen as preferable to advance warning signs and cones