From the info you provided, you could potentially counter claim for harassment under the Equality Act 2010. In the event that these statements cause you to lose your job, you could potentially claim for defamation under the Defamation Act 2013.
There are also many instances in which defamation in the workplace could occur. For instance, a surprise meeting may prompt an employee to circulate emails which falsely claim this was held to discuss misconduct, defaming the individuals involved.
Rather your employer or the person who made the defamatory statement must prove that it is true. If your case is successful you may receive damages as decided by the High Court, dependent upon the seriousness and extent of the damage to your reputation.
To win a defamation case, you need to prove that the statement was defamatory, was published, refers to you, and has yielded or is likely to cause severe harm to your reputation.
Defamation that causes long-term damage, particularly if it affects your career, social standing, or personal life, will result in higher damages than something short-term that might be forgotten within a year. The more severe and lasting the harm, the greater the compensation.