Most employers will waive strict academic requirements if a candidate clearly demonstrates they have intelligence and are able to do the job but it does depend on the job. Some definitely do require a certain amount of academic background.
What sort of job would you like to do? You mentioned the police force earlier on but you do need problem solving skills and a good memory to be a police officer. Attention to detail and being able to assess a situation fairly quickly are important. From what you have said about yourself, they are not your strong points. You're not alone there, I know I would be absolutely useless at that because I am by nature unobservant and frequently don't notice what others see even if right in front of me. I also don't have quick reflexes, tend to ponder and procrastinate. That's me and I wouldn't ever have wanted to join the police force anyway but what I am saying is that we all have different strengths and weaknesses.
Another thing that does not go in your favour is that you've never worked since leaving school. Most people do work, even if it is only something, for example, like assisting in a laundrette or filling shelves in a supermarket. I am really surprised you have been able not to work, especially before having children.
I do get that you lack confidence.
What things are you good at, nicknickers, and do you read for pleasure, sew, cook, drive? There must be something that you like doing and manage quite well. Maybe build on that.
Ask at your local jobcentre if there is a member of staff specifically trained to help and guide people into work. She or he will be able to assess your capabilities and then maybe the right job will appear but you have to be realistic.
Good luck.