Don’t carry anything as a ‘self defence weapon’ based the theory that it’s legal for self defence.
It is correct that it is legal for you to defend yourself, and also that you can use whatever you have to hand.
Guns (and tasers etc)- clearly illegal
Pepper spray - illegal, but there are legal alternative irritants for use against people or dogs. Make sure you buy from somewhere legitimate to ensure that what you get is actually UK legal, and ‘anti dog spray’ could be the best option especially for runners etc - if you were attacked by a person and defended yourself then it will work just as well
Knives - definitely don’t. There are ‘legal’ situations to carry knives but it’s not as simple as saying “under 3”’ is legal - if it’s in your bag for self defence then it’s an offensive weapon.
Think about what you would do with jt anyway - you only manage to cut and enrage the attacker more
(Note that I also knew someone who had repeatedly driven under driving bans, on one stop the police fully searched his car to get as much as possible on him. He had numerous knives of varying sizes in his car, but had valid reasons due to his job. He had a fruit knife in his glovebox which they prosecuted him for - not for his work, and they treated it as an offensive weapon that was close to hand
They knew he wasn’t carrying as a weapon but they were seeking things that he would take notice of to try and stop him driving when banned)
Don’t buy any ‘self defence key rings’. These items are illegal because they are a weapon (even if the seller try’s to tell you it’s legal), but if you know how to use them then you can use a key, pen etc
If you may use keys to jab or scratch an attacker then try to keep your car keys or house keys separate if they get dropped or taken off you then can you escape?
If you have parked to go on a run, then you can’t get in your car if you’ve dropped your car key. If you are jogging in the street and drop your house key then you can’t open the door
A spare set of random keys can happily be dropped (but don’t say that you were carrying just random keys)
Hairsprays, body sprays etc, hair brushes etc are perfect - they are normal things that you could have in a bag.
Even if it came down to it a runners plastic bottle that can be squeezed to squirt out your water in their face is better than nothing - it’s a sudden thing that can give you a moment of time to run away.
Get some form of self defence training
Dont think that kicking in the balls will do any good - it does hurt, but they could dodge or you could miss, and it depends on how good a kick you do. You could also get your leg or foot grabbed putting you at a disadvantage
Go for shins, stamping on feet depending on footwear, scratching faces etc
Don’t try to be a super ninja fighter - hit hard & fast, be loud and get away