Personal Statement - Innovative Ideas

Can I put my innovative unique idea in personal statement or cover letter related to cybersecurity which facing by UK overall half of the attack in that domain but there is no publication of my idea anywhere else? I tested something personally and in my mind only right now.

I have a proper plan for this.

sounds like you have some very good evidence and plan! If you have some external evidence to support your idea (eg. letters from domain experts in the UK to echo your statement), it will make it even strong. Btw, the plan is needed in your personal statement.