Transparent 746 Telephone
They have the traditional 746 shape, but with a transparent casing so you can see what makes the phone work. They were originally used in telephone exchanges and there are now less than 100 in existence. They been reconditioned both inside and out and are fully compatible with modern BT systems or adapted at no extra cost for Telewest users.
The transparent 746 telephone costs £145 from Pedlars.