excitable atc?? your honour, i object!!
so for example you would just return to heathrow and not tell anyone until you were approaching the airport?? i submit that you would not be welcomed with open arms. As has been mentioned, you need not tell us over the r/t, however i would expect to hear from your company informing us of the situation, as this could greatly effect the routing that you are given and the choice of destination, as well as where you will be parked once you landed.
i realise that your prime responsibility is to those you have onboard, but i personally would not like to put you over the centre of a large city just incase the worst did occur.