Earlier quoted context omitted.
The UK is basically 'at will' for the first two years. I've never worried about getting fired in that period. Just pick who you work for carefully and make yourself valuable.
The standard probation period is six months in the UK. I haven't encountered two years yet, is that even legal? And it's called probation period for a reason, it's a time for both sides to figure out if the arrangement works out and be able to quit with no or little notice otherwise. After that, 3 months notice periods are completely normal so it's good to not get locked into that from day one.
https://www.stephens-scown.co.uk/employment/employment-right...