Hello, sorry for not getting back to you sooner, I had problems accessing the site over the last couple of days.
You have a couple of options. First of all you can try and report this to the police. There could be offences under the Computer Misuse Act that he is guilty of although it would be for them to investigate and determine if that is the case. At least it is a free service and you have nothing to lose.
If you were looking at the civil route, then whilst there may be options for you to sue, such as on grounds of malicious falsehood or defamation, these can be rather expensive to pursue. For example a claim for defamation will easily set you back in the region of £15-20k. The issue then is that even if the court finds in your favour, it does not guarantee you will get any compensation. The person, as an individual, may not have that many assets or money in general to be able to satisfy the claim. They could for example just declare themselves bankrupt. They could also completely ignore the court’s judgment and leave you in a position where you are left to try different enforcement methods to try and enforce the judgment against them (e.g. bailiffs, earning adjustment order, property charge, etc). Each of these will cost you more money and you will not be guaranteed a successful outcome as it will be a trial and error exercise until you find something that hopefully works.
Therefore, as you can see the legal route is possible but not without its risks and it could easily leave you with a large legal bill and further liabilities which are best avoided. As such the police will be your best bet in the circumstances.
I trust this has answered your query. I would be grateful if you could please take a second to leave a positive rating (selecting 3, 4 or 5 starts at the top of the page). If for any reason you are unhappy with my response or if you need me to clarify anything before you go - please get back to me on here and I will assist further as best as I can. Thank you