An year into a job role, are there any sort of complications to immediately leaving a permanent position, when in contract employee is required to give 3 months notice ?
Obviously yes - you will have as much trouble as the employer wants to cause you. You would be in breach of your contract; if your employer thinks that causes them damages, they can sue you or your next employer. That’s what contracts are there for.
This is something that you should really negotiate. OTOH if you need to leave because of a sick family member, or to serve a jail sentence, your employer may be understanding.
You'll be in breach of contract. It all depends on what sort of monetary/criminal/civil implications there are but nobody here would know as you're the only one with the actual contract. I suggest you read it, and possibly consult a lawyer on what your options are. It's probably best to simply give the notice.