You say you have already lost all of your no-claims over a false claim. So quantify your 'damages' (the total amount this has cost you and is expected to cost you). Then make a 'Small Claim' against the lying other driver in the hope it eventually goes to the Small Claims Track of the County Court and you get a CCJ against that person. Once he/she knows you are calling his/her bluff, they may back down and pay up: www.gov.uk/make-court-claim-for-money/overview/