Well, Chris, you could take 2014/2015 as an example. PHE recorded 28,330 deaths from influenza in England alone. This contributed to excess deaths in England and Wales that winter of 43,900 (36,300 of which were in the 75s and over). According to ONS '...influenza-like-illness rates rose above the epidemic threshold in week 50 and remained above or at that threshold until week 14':
https://www.ons.gov.uk/peoplepopulationandcommunity/birthsdeathsandmarriages/deaths/bulletins/excesswintermortalityinenglandandwales/201415provisionaland201314final
There were 50,100 excess winter deaths in England and Wales in 2017/2018, with influenza being a major cause of the rise over the previous winter's figure. Then there was 1999/2000...
WHO estimate up to 650,000 annual influenza-associated deaths globally.