What precautions did the British government take for the anticipated German attack in 1939

The British government took many different kinds of
precautions, ranging from large scale defensive works to the issuing of instructions so
that the general populace would know what to do in case of invasion.  Let us look at a
few of these.

• Defensive lines.  The government
  started to prepare defensive positions from which British soldiers would be able to
  fight if the Germans landed.


• Attempts to confuse Germans
  who did land.  The British government had road signs and mileposts removed or defaced. 
  They took down the signs on train stations.  The point was to make it so German soldiers
  would not know where they were.


• Instructions to the
  public.  The government started preparing people, doing things like telling them not to
  leave their homes unless they were told to evacuate.  The point of this particular order
  was so that fleeing civilians would not block roads.  By doing this sort of preparation,
  the government hoped to avoid chaos and
  confusion.