. ▁Between ▁ 1 8 4 9 ▁and ▁ 1 8 5 7 , ▁two ▁Mart ello ▁to wers ▁of ▁dressed ▁Port land ▁stone ▁were ▁constructed ▁at ▁the ▁south - western ▁and ▁north - western ▁corner ▁of ▁the ▁dock yard ; ▁both ▁were ▁g arrison ed ▁by ▁ser ge ants ▁of ▁art illery ▁and ▁their ▁families . ▁ ▁In ▁the ▁ 1 8 5 0 s ▁a ▁h utt ed ▁enc amp ment ▁was ▁established ▁nearby ▁on ▁L lan ion ▁Hill . ▁In ▁ 1 9 0 4 ▁this ▁was ▁replaced ▁by ▁four ▁brick - built ▁bar rack ▁blocks , ▁designed ▁to ▁house ▁a ▁thousand ▁troops . ▁The ▁new ▁L lan ion ▁Bar ra cks ▁was ▁' the ▁first ▁bar ra cks ▁to ▁be ▁constructed ▁with ▁a ▁separate ▁area ▁for ▁cook ing ▁and ▁ab l utions ▁and ▁was ▁one ▁of ▁the ▁most ▁modern ▁in ▁the ▁country '. ▁ ▁The ▁town ▁remained ▁g arrison ed ▁with ▁troops ▁until ▁ 1 9 6 7 . ▁ ▁R AF ▁base ▁▁ ▁With ▁the ▁closure ▁of ▁the ▁dock yard ▁in ▁ 1 9 2 6 , ▁the ▁year ▁of ▁the ▁General ▁St rike , ▁un emp loyment ▁was ▁high ▁through ▁the ▁Great ▁De pression ▁until ▁ 1 9 3 1 ▁when ▁No . ▁ 2 1 0 ▁Squadron ▁R AF ▁arrived ▁equ ipped ▁with ▁South am pton ▁II ▁flying ▁boats . ▁For ▁almost ▁ 3 0 ▁years ▁the ▁Royal ▁Air ▁Force ▁was ▁based ▁at ▁P embro ke ▁D ock . ▁During ▁ 1 9 4 3 ,