Malicious Prosecution is the institution of an unsuccessful criminal,bankruptcy or liquidation proceedings against an innocent parson.It is done only with a malicious intention and not in furtherance of justice.It is also unreasonable and damages,the reputation of an innocent person.
Essentials:
1. The plantiff must have been prosecuted in a criminal case or Bankruptcy or liquidation proceedings by the defendant.
2. The case for the proceedings must be terminated and the plantiff must be acquitted or at least  discharged.
3. The defendant must have launched the case without reasonable and probable cause.If the defendant has filed the case under honest and reasonable belief,then it is not actionable under the tort of Malicious Prosecution.
4. The prosecution must be instituted with malicious intention.There must be wrongful and willful intention to punish the plantiff.The malicious intention may be present even from the commencement of case,or subsequently after the case is filed.
5. The plantiff must have suffered some damages or loss in person,reputation or pocket as a result of prosecution.
Eg:
One "M" suffered injuries in a Railway accident.The Railway Authorities paid heavy compensation as his wounds were certified by a Doctor "B".Later on,the Railway Co.,came to know that "M" and"B" conspired to secure damages from them.So,the Railway company sued "B" and"M" for conspiracy.The case ended in the acquittal of "M" due to insufficiency of evidence.The doctor and "M" sued the Railway Company for Malicious Prosecution.However,the court held that there was no Malicious Prosecution,as the case was filled on reasonable grounds and with honest belief.
Only if all the above essentials are fullfilled,the tort of malicious prosecution can be instituted.