It's all pure nonsense.
1. you would likely be charged under the Malicious Communications Act (1988) for which you would be arrested and interviewed under caution, as it's an indictable offence
2. After which, the file would then be passed onto the 'Criminal Protection Service' - sorry, Crown Prosecution Service (CPS), who having a mandate, to stitch up anyone they can to make their numbers good - especially low level non-criminal offences - would then agree to proceed.
3. Thereafter, you would be subject to either affording your own legal defence, or a legal aid retard, who doesn't give a damn as to the law, or your innocence. In all likelihood, the Magistrate, would defer the case to the Crown, since making threats towards serving MPs is rather stupid at the best of times, even more so, after the death of Jo Cox.
4. At Crown Court, if you earn more than 32k a year, you will be wholly reliant upon your own financial means to obtain a proper legal defence - expect to pay at least 20k, preferably 50k if you are actually innocent and want to be protected against the relentless pummeling of the State prosecution, who'll use every manner of logical fallacy, loopholes in the law and court theatrics, to paint you worse than lucifer himself.
If on the other hand you earn less than 32k, then again you will be assigned a half drunk, legal aid lawyer, who really cannot be arsed, but will properly do a line of coke in the bathroom, to invigorate himself to put in something that at least looks like he tried...
5. At the end of said trial, the judge and barristers of both the prosecution and the defence will no doubt have a 'chin wag' at the wives' gala dinner or some other luncheon to do with the lodge, whereupon they will mock you for how pathetic you were and the amount of money they fleeced from you and the taxpayer, and buy themselves another koi carp for the moat around their mansion.