The photos that the Independent are using at North American elk - Cervus canadensis. However, the species that they are actually looking to introduce are Aces alces - Eurasian elk, which are what North Americans know as moose.

The Guardian did get this right a few days back.

ETA: they have now corrected the photos.

I hope they remember to reintroduce wolves too. Otherwise they’re going to learn an important lesson about balancing ecosystems, like we did here in America. We have to call the deer herds occasionally, they will strip the bark off of every tree in the area if you let them.