Police have released a CCTV image of the van, which they described as a “black, modified, VW Transporter with a 02 registration plate”.
The van had three alloy wheels, with the alloy on the front nearside wheel missing. All of the alloys were of a BBS make.
Officers say it had no rear windows, no writing on the side, chrome sidesteps along the skirts and a sliding side door.
Meanwhile the boy was described as white, around four foot tall and about six or seven years old.
He was wearing a red t-shirt and navy blue jeans and was riding a yellow and black Frantic Giant mountain bike, which was left at the scene.
Officers have said that anyone with information should call 999.