If a driver cannot obtain a view through the caravan to the rear, then the towing vehicle must be fitted with extension mirrors to both the offside and the nearside.
Many drivers believe that because they are towing with substantial 4x4 vehicles that these mirrors are not required. When police check caravan outfits, one of the most common problems they find is a lack of towing mirrors - something that could potentially cost you more than the price of the mirrors!
If in doubt, check with your dealer.
Requirements in new cars from January 2010
On 26 January 2010, a European Directive (EEC 2003/97) changed requirements for rear view mirrors for new passenger cars and motorhomes first used after that date. All extension mirrors must comply with the constructional and testing requirements of the EEC Regulation (EEC 2003/97) and show the new e-mark.