If you have enough fuel and the aeroplane is still flyable etc, then on suspecting a radio and transponder fail you could use the emergency triangle procedure to give ATC a clue as to what has happened. OK, technically you're supposed to be lost as well for that, but it's pretty much your only means of communication if you're out of sight of the tower. Once you near the airport you can use switching of your nav and lading lights to indicate that you are compelled to land. I'm assuming that these signals are valid everywhere.
In terms of the lawyers, in the UK departure from the rules of the air is permitted for the avoidance of imminent danger, provided that written details are provided to the competent authority within 10 days (article 160 of the ANO).