Why factories are not located in Inner-city areas any more?

Industries were expanding at such a rate that they were taking up all the room in the inner-city areas.  As we already know there is limited room in the inner city, and it would have been impossibility for the industries to expand any more.  If they did expand, it would mean that they were expanding into residential areas, which is another impossibility.  Once the factories had reached their full capacity in the areas they were situated, they were forced to move.  This is a lack of expansion space.

Buildings/factories often became out of date.  New technologies had been introduced into the industries, and the basically the old factories were unsuited to the modern techniques.  Often the buildings became derelict, and too bad to repair.  The new factories were bigger and better, and could not expand in the inner city therefore they moved into the suburban areas.  As the new companies looked for places to expand into, they tended to avoid the inner city.  

The infrastructure was poor.  The roads were too small to accommodate all the large vehicles.  People living in the inner city tend to park their cars on the side of the road therefore causing a blockage, or narrow roads.  As the factories closed and moved, so did the majority of the population.  As a result shops and restaurants suffered, and struggle to find business.