OF all the men who messed up the life of Mary, Queen of Scots, it was her second husband Henry, Lord Darnley, who was the worst both in character and deed. She had only herself to blame for that as the Queen married him out of lust and quickly grew to regret her choice.

It really was case of “marry for pleasure and repent at leisure”, though it was only a matter of months before Mary realised what her husband really was – a wastrel, a drunk, a bully, a hotheaded fool, an immoral sexual deviant and a jealous youth who coveted her Crown.

Darnley quickly became more demanding of Mary and portrayed himself as joint monarch. Even after the Chaseabout Raid had ended with the Earl of Moray in exile in England, Darnley could take no credit for that, the Earl of Lennox being the military commander and Mary herself leading her army to success, which made the Scottish public admire her even more, though their adoration did not extend to Darnley.

At that point in exile, Moray himself seemed to have made a major misjudgement. Rather than get succour from Queen Elizabeth, instead he got a public ticking off for daring to rebel against Mary – Elizabeth and her advisers realised that it was not a good look for any queen to be challenged, hence the vehemence of her denouncement of Moray. Except that most historians now conclude that Moray’s supposed humiliation was a piece of deceitful propaganda, the evidence for that conclusion being Moray’s royal permit to soon travel north to Newcastle where he lay in wait for events to turn his way.

Even as this was happening in England, the King Consort in Edinburgh started to go completely off the rails. You can forgive him his immaturity – he was still in his teens – but not his vaunting ambition or ill-treatment of Mary. He renewed his demands for the Crown Matrimonial which would rank him equal to the Queen, which Mary understandably refused, then began to lead a dissolute lifestyle, consorting with his young friends and visiting known prostitutes.

There is some reason to believe that he gave Mary some sort of sexually transmitted disease, but whatever the reason, Mary turned against Darnley quite quickly in late 1565. Ambassador Thomas Randolph reported to Robert Dudley: “I know for certain that this Queen repenteth her marriage: that she hateth him and all his kin.”

That one verdict is why I want to spend some time on analysing Darnley and what he did. You look at his actions and try to find some reason to exonerate Darnley, but frankly the man had no redeeming features. He also seems to have been unaware of his diminishing standing and popularity, or maybe like similar narcissists Donald Trump or Boris Johnson, he didn’t care and just kept going regardless.

Another person who was having second thoughts was Darnley’s own father, the Earl of Lennox, who tired of his son’s excesses, made his excuses, and left the Court. Lennox may also have noted the increasing influence of two men whose interests were against his – James Douglas, the 4th Earl of Morton and James Hepburn, the 4th Earl of Bothwell.

I will deal extensively with these two figures next week in the final column on the powers behind Mary’s throne, and show how, for all their machinations, the likes of Darnley, Lethington, Moray, Morton and Bothwell all met a sticky end.

By the time Lennox opted out of Court, Mary was pregnant with his grandson, and realising that a child would relegate him further down the line of succession, Darnley did not celebrate that conception. On the contrary he got involved in a plot to make Mary miscarry.

Make no mistake, having researched the event thoroughly, I have no doubt that Darnley joined in the murder of David Rizzio in March, 1566, with the main intention of making his wife miscarry.

The other plotters may have been trying, as they said, to uphold the Protestant religion in the face of a Catholic resurgence aided and abetted by Rizzio – a spy for the Vatican? – but Darnley’s motivation came from his new-found distaste for his wife and his ambition to be the monarch.

The King Consort had become very jealous of David Rizzio, his one time friend – they may even have been lovers – while the Protestant Lords had become increasingly angry at the Italian’s influence over the Queen. The usual two and two were put together and no matter who first claimed five, the rumours began to circulate that Rizzio and Mary had been intimate.

The National: Mary Queen of Scots with her Italian private secretary David RizzioMary Queen of Scots with her Italian private secretary David Rizzio

Some even claimed that the Queen was carrying Rizzio’s child. Some sources told the story of Darnley going to his wife’s chamber in the Palace of Holyroodhouse and finding Rizzio hiding in a cupboard, but Darnley himself made no such claim.

Whether she and Rizzio were lovers – if they were, would his DNA be found in the current royal family? – Mary defended her honour and his, thus leaving Darnley with what he saw was his only option to concoct his devilish plot with his friends who had formed a separate Court away from the Queen.

Ironically, had Moray and Secretary Maitland still been at Court, they would probably have advised her as to her husband’s intentions and the danger to Rizzio. But the former was in England and Lethington was stuck at home – in what is now Lennoxlove – in a huff because Mary favoured Rizzio over him.

The plotters bonded together and, though they all never signed an actual written bond, which was the usual way of doing this sort of thing in those times, as we shall see, Darnley himself signed articles to give comfort to his fellow plotters. Basically, he promised that there would be no comeback on them, and that is the evidence of his vile involvement.

Thanks to Patrick Ruthven, the 3rd Lord Ruthven, who kept a copy, we know exactly what Darnley said: “Be it Kend to all men by these present letters: We, Henry by the grace of Good King of Scotland, and Lieutenant to the Queen’s Majesty; for so much we having consideration of The gentle and good nature, with many other good qualities in her Majesty, we have thought pity, and also think it great conscience to us that are her husband, to suffer her to be abused or reduced by certain privy persons, wicked and ungodly, not regarding her Majesty’s honour ours, nor the nobility thereof, nor the common-weal of the same, but seeking his or her own commodity and privy gains, especially a stranger Italian called Davie; which may be the occasion of her Majesty’s destruction, ours, the nobility, and common-weal, without hasty remedy be put thereto, which we are willing to do; and to that effect we have devised to take these privy persons, enemies to her Majesty, us, the nobility, and common-wealth, to punish them according to their demeritis; and in case of any difficulty, to cut them off immediately, and to take and slay them wherever it happeneth.

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“And because we cannot accomplish the same without the assistance of others therefore have we drawn certain of our nobility, Earls, Lords, Barons, freeholders, gentlemen, merchants, and craftsmen, to assist us in our enterprise, which cannot be finished without great hazard.

"And because it may chance that there be sundry great personages present, who may endeavour to gainstand our enterprise, where through some of them may be slain, and likewise of ours, where through a perpetual feud may be contracted betwixt the one and the other; therefore we bind and oblige us, our heirs and successors, to the said Earls, Lords, Barons, gentlemen, freeholders, merchants, and craftsmen, their heirs and successors, that we shall accept the same feud upon us, and fortify and maintain them at the uttermost of our power, and shall be friend to their friends, and enemy to their enemies; and shall neither suffer them nor theirs to be molested nor troubled in their bodies, lands, goods, nor possessions, so far as lieth in us.

“And if any person would take any of the said Earls, Lords, Barons, gentlemen, freeholders, merchants, or craftsmen, for enterprising and assisting with us for the achieving our purpose, because it may chance to be done in presence of the Queen’s Majesty, or within her Palace of Holyrood House, we, by the word of a Prince, shall accept and take the same on us now as the, and then as now, and shall warrant and keep harmless the foresaid Earls, Lords, Barons, freeholders, gentlemen, merchants and craftsmen, at our utter power. In witness whereof we have subscribed this with our own hand at Edinburgh, the 1st of March, 1565”.

Now that may have been a forgery to show how Darnley really did play a leading part in the plot, but it has long been accepted as genuine, as it has the ring of truth and was just the sort of thing that Darnley would say to get people to do his dirty work.

The English Court and Queen Elizabeth knew what was coming, because Thomas Randolph and William Cecil had told them that Darnley would have Rizzio murdered and then try to usurp the Crown.

The timing of all this was crucial because on March 12, a Bill of Attainder was due before the Scottish Parliament, which would have removed all the property, titles and money of the Earl of Moray and his fellow rebels of the previous year. Any action against Rizzio and the Queen would have to take place before that date so Parliament could be dismissed, and would have to be undertaken with extreme prejudice, to coin a phrase, which meant the killers had to be experienced and able to kill an innocent man in a savage way.

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There are several theories about why Rizzio was murdered, but when you consider the events as they unfolded, it is clear that the Protestant Lords conspired together and drew Darnley into their plot, though he may have been in it from the beginning. For a start, Darnley had no experience of assassination or murder, and it was going to take much tougher men than him to actually carry out the deed. He just wanted to end the Queen’s pregnancy – and if that meant getting rid of Rizzio, then so much the better.

On the evening of Saturday, March 9, 1566, Mary was in her private rooms eating supper with her attendants including Rizzio. The Earl of Morton with about 100 men quietly approached the palace and sealed off all the exits. We have various accounts of what happened next and they all agree on the main details. Darnley came in from a stairwell that linked Mary’s rooms with his, and then Ruthven burst in the main door fully dressed in armour.

Ruthven said to the Queen that Rizzio had been “overlong here” and despite her commanding him to leave on pain of committing treason, Ruthven advanced on Rizzio while Darnley held on to Mary. Armed men then burst into the room, including George Douglas, Lord Patrick Lindsay, Patrick Bellenden and Andrew Ker of Fawdonside. The latter is said to have presented a pistol to her baby bump, and Mary became convinced then and ever afterwards that the conspirators’ real intention was to assassinate her and her unborn child.

It is disputed as to who actually stabbed Rizzio first, but realising that he was the target, he pleaded with the Queen to save him. She could do nothing as Darnley held on to her. The conspirators closed in with their daggers and then dragged Rizzio into the next room where he was stabbed more than 50 times. Though he probably didn’t wield it, the last dagger plunged into Rizzio’s side and left there belonged to Henry Darnley, King Consort of Mary, Queen of Scots.