This answer has been update for Blender 2.81. The original one was mistakenly written for Cycles.
There are three parts of the problem that need to be addressed:
- In Blender lights don't create any visibile geometry, therefore you don't see the source of the spotlight that is emitting the light.
- The spotlight placed inside a closed object wasn't emitting light to the outside of the object.
- The light cone is only visible when geometry is hit by it or volumetric effects are introduced.
The first problem can be fixed by assigning a shadeless or emissive material to the front of the torch.
The second issue doesn't exist in Blender 2.81 and later when using Eevee, since lights can pass through the enclosing object. However there is no need to put the light inside the object. You can place it slightly in front of the torch and it will give you the desired visuals as well. For Cycles you will either have to place the spotlight outside of the object as well or assign a transparent material to the front which allows the light to pass through.
Spotlight with emissive front, spot light placed outside with a spot size of 45°, contact shadows enabled and an irradiance volume to bake indirect light.
Spotlight with emissive front, spot light placed outside with a spot size of 80°, contact shadows enabled and an irradiance volume to bake indirect light.
An alternative solution when using Cycles is a mesh light which could be placed inside the torch. Since mesh lights are actual geometry, they are also visible in the render, thereby solving problem 1). This approach would require to model an approximation of the torches interior. However this isn't as versatile as using a spotlight, since the shape of the light cone would be determined by the geometry of the torch and the mesh light. Therefore, adjusting the look is much more difficult compared to the settings of the spotlight.
In order to solve problem 3) you would either need to ensure that the torch hits objects in the scene to make the light cone visible, e.g. walls, or add atmospheric effects simulating dust in the air. This can be accomplished by adding a cube into the scene that is scaled to encloses the volume that should scatter the light. Assign a Volume Scatter material with a low density to the cube.