Protecting your garden with fencing, hostile hedging, security lighting, cameras and locked gates will help to keep your plants safe but you may to wish to give additional protection to especially treasured plants. Plant anchors can be used to protect valuable specimens. Also try putting a layer of chicken wire under the surface of the soil when planting to prevent plants from being removed. Plant pots can be chained and padlocked through the drainage hole.
Allotment holders have problems with their crops being picked and stolen. Guidelines for garden security in terms of securing the perimiter and ensuring visibility apply but unfortunately sometimes the theft is carried out by other allotment holders. If crop theft becomes a serious problem at your allotment it may be worth considering a security camera.
Home and Garden Insurance from Alan Boswell Group covers loss or damage to garden contents up to £10,000, which includes up to £500 cover per plant, shrub or tree - see Key Features of Cover.