If the phone is in your name, then you may find:

To be of use.  If the phone is in your wife’s name, then:

https://community.idmobile.co.uk/cancelling-an-id-mobile-plan-109/how-do-i-cancel-my-id-mobile-plan-43727

Hey there @Tony Freeth, we’re very sorry to hear about your loss.

As kindly advised by @LordFeltchly, the link sent above will assist in cancelling the contract, if it’s under your name.

If under your Wife’s name, then please contact our live-chat via the link below, and give us your Wife’s full name, full address including postcode, email address and phone number, as well as a copy/photo of the death certificate, and we can close down the contract and cancel any remaining charges.

https://www.idmobile.co.uk/live-chat

Thanks,

Tylre