Crocuses are a lovely reminder that spring is on the way. Both globally and across the UK, purple crocuses are planted to remind us of humanity’s pledge to eradicate polio.

In the years when my parents were born, there were as many as 8,000 cases of polio each year acquired in the UK, leaving many families bereaved and tens of thousands of children with lifelong disabilities. An effective vaccine was developed in the late 1950s, and as a result of the success of its rollout in the UK, there has been not a single UK-acquired case of polio in my lifetime. It’s easy to forget the astonishing and unprecedented progress we made in public health in the twentieth century.

We haven’t eradicated polio worldwide quite yet, though we’re getting close, with only tens of cases reported each year. Two of the three strains of polio have been consigned to the history books. The purple crocuses should remind us that we still need to finish the job.