 In all, around 70 forts and batteries were constructed around the English coast as a result of the Royal Commission's report.An existing gun battery, Grain Tower, already existed just off the shoreline at Grain, about away from the site of the later Grain Fort.It had been built in the style of a Martello tower between 1848–55 but the introduction of powerful and accurate rifled muzzle loader (RML) guns during the 1850s made it obsolete as soon as it was completed.