Radio works in tunnels.

[chudleighpaul]

Until recently I could never get radio reception in the Blackwall Tunnel, but recently this has changed, and now the reception is near perfect.

How is this achieved?

 

[Lee H]

Potentially a relay? It's a bit of a traffic balckspot, so it would make sense to have a relay for the traffic news. This could have been off or faulty before. I think the Mersey tunnel has the same thing.