@Upt' North you just knew someone was going to do this didn't you
UK rules are shown below.... they vary for all other European nations!
'You can use motorbikes with an engine size of 125cc or more to tow small trailers.
Your motorbike has to be clearly and permanently marked with its ‘kerbside weight’.
Kerbside weight is the weight of the vehicle without passengers or any load but with a full tank of fuel and filled up with the necessary oils, water and fluids.
The trailer must be no more than 1 metre wide and must be clearly and permanently marked with its unladen weight.
When the trailer is loaded it must weigh no more than 150 kilograms or 2/3 of the kerbside weight of the motorbike - whichever is lighter.
When hitched, the distance between the end of the trailer and the rear axle of the motorbike must be no more than 2.5 metres.'
Source:
www.gov.uk