The fatal crushing of a three-year-old boy by a runaway trailer has led to a new safety campaign.
Freddie Hussey suffered head injuries when he was hit by the portable cabin that had detached from a Land Rover Defender.
The Driver and Vehicle Standards Agency (DVSA) has produced an online guide showing motorists how to check their trailer is safely secured before towing objects such as caravans, horseboxes and boats.
The advice includes checking brakes, lights and the height of the coupling as well as how to use a breakaway cable.
Transport minister Andrew Jones said: "I was shocked and saddened by the death of three-year-old Freddie Hussey.
"It is absolutely essential that drivers carry out a few quick and simple checks to make sure their trailer is safe so we do not see a repeat of this awful tragedy.
"This campaign will help drivers to make sure they are towing safely and will save lives in the process."
DVSA chief executive Gareth Llewellyn warned motorists they must ensure anything connected to their vehicle is used safely.
He said: "There is no excuse for not being informed. Even a short journey with an insecure or unroadworthy trailer puts lives at risk."
The campaign is supported by the National Trailer and Towing Association and the Society of Motor Manufacturers and Traders.
Freddie was killed in Bedminster, Bristol, in January 2014 as he walked with his mother.
Delivery driver Tony Davies, of Berwick Lane, Hallen, Bristol, was driving the Land Rover when the trailer became detached.
He pleaded guilty to causing death by careless driving at Bristol Crown Court.
He received 200 hours of community service and was banned from driving for six months.
The court heard the tragedy was attributed to a handbrake lever being in the wrong place, which caused the trailer to come adrift.
It travelled about 10 or 12 car lengths before mounting the pavement and crushing Freddie against a wall and a telegraph pole.