Banging pipe

I live in a terraced house that is one in a block of 4 houses. All four houses share one outside stop value and then have a stop valve in the house. My mains water pipe in the house has started to bang randomly through out the day. It isn't being triggered by me using cold water so thought it could be caused by a neighbour using water and causing a sudden drop in the pressure in my pipe.If I put my hand of the pipe I can feel slight movement in the pipe. Today as an experiment I turned off my mains but the intermitent banging continues so I don't think it can be causwed by a drop in pressure. I have yet to ascertain whether it is being caused when a neighbour uses mains water but will ask them to turn on and off their tape a few times to see. I don't understand how the banging can continue if my mains water is turned off in the house though. One last thing to mention is that there are no brackets fastening the pipe to the wall as the pipe travels from the floor to the upstairs and it would not be easy to do so as there some old unused gas pipes in the way. Also the boiler off and washing machine is off.
Thanking you in advance for any suggestions to the cause.