St Mawes 12-pdr Battery was built between 1900 and 1904 to help protect the minefield between St Mawes Castle and Pendennis Castle. The battery was located up the hill behind St Mawes Castle to give a better field of fire than the 6-pdr Battery in the Castle. This 12-pdr Battery was built in three phases. First to be built between 14th August 1900 and 1st July 1901 was two 12-pdr gun emplacements with underground magazine and shelters to the rear. The cost of this work was £3338, slight under the approved budget.
This was followed by two additional 12-pdr emplacements and the caretakers cottage. This work was carried out between 21st July 1903 and 1st October 1904 and cost a total of £1,887, again slightly under budget.
A Electric Light Control Post and a Mining Control Post were also built on the west end of the battery at various dates.
The Battery was decommissioned in 1907.
The whole battery and associated works remain well preserved.
TNA WO 192/274 Fort Log
TNA WO 78.4850