The Economist wrote before the 2017 UK general election:
The average incomes of retired households are now higher than those of working ones, once housing costs are accounted for. Small wonder that they want to keep the status quo. [...] elderly folk have also been coddled by the Conservatives—most obviously by the “triple lock” on the state pension, which David Cameron, Mrs May’s predecessor, implemented in 2011. It ensures that pensions rise in line with whichever is highest: inflation, earnings or 2.5%.
The IMF has called it an "unsustainable method of indexation, poorly targeted to those most in need, and not in line with international best practices".
Do any other countries have a "triple lock" system like that?