There are a huge number of threats that have escalated in recent years
the main ones I see would be
climate change coupled with El Niño - so that’s weather problems like extreme storms that can take down water and electricity and comms and make getting food to affected areas difficult even if you are not flooded or blown away yourself. This can also have an impact on food supply chains - poor harvests , rising prices, countries refusing to export food - the UK hasn’t been self sufficient in food for probably 100 years
war escalation in the Middle East - this can affect supply of fuel and goods from China. More likely to lead to increase prices and food scarcity. The fuel problem affects fertilisers which impacts yields. We have also destroyed our soil in search of short term cheap food which makes us more reliant on fertiliser
cyber attack probably from an increasingly desperate Russia but there are other hostile nations . this is more likely to affect electricity and comms systems. Electricity down means no heating or water ( pumped though systems which relies in power ) or lights or telly, food in the freezer is problematics, shops closed , shops can’t get deliveries any way
these threats have always existed but the lack of action over decades ( so don’t blame this government, blame the voters ) , the desire for cheap over resilient , the head in the sand approach to climate change means that these things have ramped up to quite bad levels. The reliance on interconnected systems , the removal of fuel storage, food storage means any disruption could be catastrophic