Bill Wright wrote :
I just tested this. Put my phone in a biscuit tin and rung it up. It worked.
Sounded funny though!

In the same test with both a mobile and a wireless landline phone, both
failed to ring. A similar test with cooking foil, produced the same
result. My wireless landline's base is located at a high position in
the house, so as to provide coverage right out to the back of the
garden, which it does - except it fails in the garage and fails in the
caravan.

The caravan has a metal roof, metal sides, composite front and rear
panels. My garage has a metal roof.

Your TV antenna coax is only screened by a wire mesh in the older
coaxes. Modern, better ones include both the mesh and a copper foil.

Try wrapping your ignition key in cooking foil, inserting it in the
ignition lock and starting the car.. Tell me whether it starts?