Austere, elegant, impressive. Edwin Lutyens’s Whitehall Cenotaph is a thing of beauty, a monument that embodies permanence in the face of all that is impermanent, and solidity in the face of all that is ephemeral. It’s an inspired decision to bring it indoors, for inside a hushed gallery, away from the rush of traffic and stripped of its flags and sculpted wreathes, Lutyens’s memorial can at last be properly admired as a work of art.