Potato dying

Hello
Can anyone advise as to why this single potato in a healthy row should decide to curl up and die, I thought ants maybe as sandy soil  but no activity around plant.
Any input appreciated
Thanks

Thank you JoaoLeaftide for your reply, taken your advice and removed to find a nest of light brown coloured ants beneath which surprised me given no activity or entrance holes visible around the plant, I’ve had them among my onions before but always had the tell tale entrance where you see deposits they have flicked out while tunnelling and also a few milling about. Every day’s a school day 😊