A method of resin infusing a composite preform, said method comprising: locating a composite preform on an upper tool surface of a tool; placing a first vacuum bagging film over said tool surface to cover said composite preform and define a sealed first chamber between said tool surface and said first vacuum bagging film; locating a bridge structure over said first vacuum bagging film over a region of said composite preform, said bridge structure having an underside defining a recess forming a cavity above said first vacuum bagging film; placing a second vacuum bagging film over said first vacuum bagging film and said bridge structure to define a sealed second chamber between said first and second vacuum bagging films (130, 160); communicating a resin supply with said first chamber on an upstream side of said composite preform; applying at least partial vacuum pressure to said first chamber on a downstream side of said composite preform to establish a pressure differential to drive resin from said resin supply through said first chamber, infusing said composite preform with resin; applying at least partial vacuum pressure to said second chamber, including to said cavity, whilst infusing said composite preform; exposing the exterior of said second vacuum bagging film to an exterior pressure whilst infusing said composite preform, said exterior pressure exceeding the pressure applied to said first and second chambers (140, 163), thereby acting on said composite preform outside of said region to compact said composite preform outside of said region; and supporting said second vacuum bagging film against said exterior pressure with said bridge structure whilst infusing said composite preform wherein curing said resin infused composite preform comprises heating said resin infused composite preform to a cure temperature, said bridge structure structurally failing during said heating, collapsing said cavity, such that said bridge structure does not support said second vacuum bagging film during curing of said resin infused composite preform, allowing said exterior pressure to act on said region of said composite preform during curing. locating a composite preform on an upper tool surface of a tool; placing a first vacuum bagging film over said tool surface to cover said composite preform and define a sealed first chamber between said tool surface and said first vacuum bagging film; locating a bridge structure over said first vacuum bagging film over a region of said composite preform, said bridge structure having an underside defining a recess forming a cavity above said first vacuum bagging film; placing a second vacuum bagging film over said first vacuum bagging film and said bridge structure to define a sealed second chamber between said first and second vacuum bagging films (130, 160); communicating a resin supply with said first chamber on an upstream side of said composite preform; applying at least partial vacuum pressure to said first chamber on a downstream side of said composite preform to establish a pressure differential to drive resin from said resin supply through said first chamber, infusing said composite preform with resin; applying at least partial vacuum pressure to said second chamber, including to said cavity, whilst infusing said composite preform; exposing the exterior of said second vacuum bagging film to an exterior pressure whilst infusing said composite preform, said exterior pressure exceeding the pressure applied to said first and second chambers (140, 163), thereby acting on said composite preform outside of said region to compact said composite preform outside of said region; and supporting said second vacuum bagging film against said exterior pressure with said bridge structure whilst infusing said composite preform wherein curing said resin infused composite preform comprises heating said resin infused composite preform to a cure temperature, said bridge structure structurally failing during said heating, collapsing said cavity, such that said bridge structure does not support said second vacuum bagging film during curing of said resin infused composite preform, allowing said exterior pressure to act on said region of said composite preform during curing.