As part of the expression of discontent, Thomas Blood conspired to storm Dublin Castle, usurp the government, and kidnap James Butler, 1st Duke of Ormonde and Lord Lieutenant of Ireland, for ransom. On the eve of the attempt, the plot was foiled. Blood managed to evade the authorities by hiding with his countrymen in the mountains, and ultimately managed to escape to the United Dutch Provinces in the Low Country. A few of Blood’s collaborators were captured and executed. As a result, some historians speculated that Blood swore vengeance against Ormonde. While in the Dutch Republic, Blood gained the favour of Admiral de Ruyter, an opponent of the English forces in the Anglo-Dutch Wars, and was implicated in the Scottish Pentland Rising of 1666 by the Scottish Presbyterian Covenanters. At some point during this period, Blood became associated with the wealthy George Villiers, 2nd Duke of Buckingham, who 19th-century commentators believed used Blood as a means to punish his own political and social adversaries, since his own class ranking did not allow him to meet them “in the field”. In 1670, despite his status as a wanted man, Thomas Blood returned to England and is believed to have taken the name Ayloffe and practised as a doctor or an apothecary in Romford Market, east of London. A second attempt, this time on the life of the Duke of Ormonde, followed.

Since Ormonde’s return to England, Thomas Blood had taken up residence at Clarendon House. Blood had followed Ormonde’s movements and noted that he frequently returned late in the evening accompanied by a small number of footmen. On the night of 6 December 1670, Blood and his accomplices attacked Ormonde while the latter travelled St James’s Street. Ormonde was dragged from his coach, bound to one of Blood’s henchmen, and taken on horseback along Piccadilly with the intention of hanging him at Tyburn. The gang pinned a paper to Ormonde’s chest spelling out their reasons for his capture and murder. With one of his servants who had given chase on horseback, Ormonde succeeded in freeing himself and escaped. The plot’s secrecy meant that Blood was not suspected of the crime, despite a reward being offered for the capture of the attempted assassins. In the King’s presence, James’s son, Thomas Butler, accused the Duke of Buckingham of being behind the crime. Thomas threatened to shoot Buckingham dead in revenge, if his father, James, was murdered. Blood did not lie low for long, and within six months he made his notorious attempt to steal the Crown Jewels. In April or May 1671 he visited the Tower of London dressed as a parson and accompanied by a female companion pretending to be his wife. The Crown Jewels could be viewed by the payment of a fee to the custodian. While viewing the Crown Jewels, Blood’s “wife” feigned a stomach complaint and begged the newly appointed Master of the Jewel House, 77-year-old Talbot Edwards, to fetch her some spirits. Given the proximity of the jewel keeper’s domestic quarters to the site of the commotion, Edwards’ wife invited them upstairs to their apartment to recover, after which Blood and his wife thanked the Edwardses and left.

Over the following days Thomas Blood returned to the Tower to visit the Edwardses and presented Mrs Edwards with four pairs of white gloves as a gesture of thanks. As Blood became ingratiated with the family, an offer was made for a fictitious nephew of Blood’s to marry the Edwardses’ daughter, who, Blood alleged, would be eligible, by virtue of the marriage, to an income of several hundred pounds. On 9 May 1671, in furtherance of the deception, Blood convinced Edwards to show the jewels to him, his supposed nephew, and two of his friends while they waited for a dinner that Mrs Edwards was to put on for Blood and his companions. The jewel keeper’s apartment was in Martin Tower above a basement where the jewels were kept behind a metal grille. Reports suggest that Blood’s accomplices carried canes that concealed rapier blades, daggers, and pocket pistols. In entering the Jewel House, one of the men made a pretence of standing watch outside while the others joined Edwards and Blood. The door was closed and a cloak thrown over Edwards, who was struck with a mallet, knocked to the floor, bound, gagged and stabbed to subdue him.

After removing the grille, Thomas Blood used the mallet to flatten St. Edward’s Crown so that he could hide it beneath his clerical coat. Another conspirator, Blood’s brother-in-law Hunt, filed the Sceptre with the Cross in two (as it did not fit in their bag), while the third man, Parrot, stuffed the Sovereign’s Orb down his trousers. Meanwhile Edwards refused to stay subdued and fought against his bindings. Accounts vary as to whether Edwards’ struggle caused sufficient disturbance to raise the alarm or whether the attempt was foiled in more fortuitous circumstances. Popular reports describe Edwards’ son, Wythe, returning from military service in Flanders, happening upon the attempted theft. At the door of the Jewel House, Wythe was met by the impromptu guard, who challenged him, before the young Edwards entered and went upstairs. The “guard” then alerted his fellow gang members. At around the same time, the elder Edwards managed to free his gag, and raised the alarm shouting, “Treason! Murder! The crown is stolen!” As Blood and his gang fled to their horses waiting at St Catherine’s Gate, they dropped the sceptre and fired on the warders who attempted to stop them, wounding one. One drawbridge guard was struck with fear and failed to discharge his musket. As they ran along the Tower wharf it is said they joined the calls for alarm to confuse the guards until they were chased down by Captain Beckman, brother-in-law of the younger Edwards. Although Blood shot at him, he missed and was captured before reaching the Iron Gate. Having fallen from his cloak, the crown was found while Blood refused to give up, struggling with his captors and declaring, “It was a gallant attempt, however unsuccessful! It was for a crown!” The globe and orb were recovered although several stones were missing and others were loose. Hunt and Perrot were also taken, but not punished.

Following his capture, Thomas Blood refused to answer to anyone but the king and was consequently taken to the palace in chains, where he was questioned by King Charles, Prince Rupert, and others. King Charles asked Blood, “What if I should give you your life?”, and Blood replied, “I would endeavour to deserve it, Sire!” To the disgust of Ormonde, Blood was not only pardoned but also given land in Ireland worth £500 a year. The reasons for the king’s pardon are unknown. Some historians have speculated that the king may have feared an uprising in revenge by followers of Blood, who were thought to have taken an oath to their leader. Others speculate that the king had a fondness for audacious scoundrels such as Blood, and that he was amused by the Irishman’s claim that the jewels were worth only £6,000 as opposed to the £100,000 at which the Crown had valued them. There is also a suggestion that the king was flattered and amused by Blood’s revelation that he had previously intended to kill him while he was bathing in the Thames but had been swayed otherwise, having found himself in “awe of majesty.” It has also been suggested that his actions may have had the connivance of the king, because the king was very short of money at the time. Thomas Blood was released from prison in July 1680 but had fallen into a coma by 22 August. He died on 24 August at his home in Bowling Alley, Westminster. His body was buried in the churchyard of St Margaret’s Church (now Christchurch Gardens) near St. James’s Park.