If you were the innocent victim, then yes, but you can claim any expenses from the other party.

Sorry, I was not clear enough. The claim has been settled in our favour through mib. Do I declare the accident to insurer as we did not claim through them but went with a solicitor who dealt with mib.

You've still made a claim, through the solicitor - most policies ask about "any accidents, claims or convictions" so you need to declare on two points.