A fearsome dragonfly nymph

We accidentally fished this dragonfly nymph out of the pond when clearing weed. We think it is probably a nymph of the Emperor Dragonfly Anax imperator. Emperor Dragonflies are rapid colonisers of new ponds and the young can complete their aquatic stage within a year (eggs being laid in the summer with adults emerging in the following spring/summer).
We also saw a female Emperor Dragonfly ovipositing in the pond during summer 2005. We put the nymph back into the pond and it quickly disappeared amongst the weed.