I found a UK-based mobile phone that is suitable for the elderly. It’s the Silverphone. All the features are controlled with just three large buttons, and the user can press and hold the red button to contact the emergency services. It’s also got an inbuilt speakerphone for the hard of hearing.
It cost £30 as a pay monthly, with monthly line rental of £20 and 100 minutes of calls a month, or you can buy it outright for £140 with no further payments but no free minutes.