Why has my car insurance gone up now that I've passed my driving test?
This is because as a provisional licence holder, you must be accompanied by an experienced driver at all times which, in the eyes of insurance companies, is a lower risk than when first driving on your own.
As a newly qualified driver, you'll initially pay more for your car insurance than when you were a provisional licence holder. You'll find this is the case with most insurance providers, not just 1st Central.
You'll find that your premium will come down the more years you have held a full licence and, claim-free driving can result in a 'No Claims Discount' also being applied.