Picton came to public attention initially for his cruelty during his governorship of Trinidad, as a result of which he was put on trial in England for approving the illegal picketing of a 14-year-old girl, Luisa Calderón.

[5] In 2022, the National Museum Cardiff relocated Picton's portrait from its "Faces of Wales" gallery to a side room, accompanied by descriptions of his brutal treatment of the people of Trinidad.

[10] The regiment was disbanded five years later, and Picton quelled a mutiny amongst the men by his prompt personal action and courage, and was promised the rank of major as a reward.

He did not receive it, and after living in retirement on his father's estate for nearly 12 years, he went out to the West Indies in 1794 on the strength of a slight acquaintance with Sir John Vaughan, the commander-in-chief, who made him his aide-de-camp and gave him a captaincy in the 17th Regiment of Foot.

[11] Under Sir Ralph Abercromby, who succeeded Vaughan in 1795, Picton was present at the capture of Saint Lucia (after which he was promoted to lieutenant colonel of the 56th Regiment of Foot) and then that of St Vincent.

Picton was also making money from speculation in land and slaves, and his free coloured mistress and mother of four of his children,[14] Rosetta Smith, was believed to be corruptly influencing his decisions.

Those charges related principally to accusations of excessive cruelty in the detection and punishment of practitioners of Obeah, severity to slaves, and of execution of suspects out of hand without due process.

[18] Picton was, however, tried in the Court of King's Bench before Lord Ellenborough in 1806 on a single charge: the misdemeanour of having in 1801 caused torture to be unlawfully inflicted to extract a confession from Luisa Calderón, a 14-year-old free mulatto girl suspected of assisting one of her lovers to burgle the house of the man with whom she was living, making off with about £500.

The torture applied ("picketing") was a version of a British military punishment and consisted in principle of compelling the trussed-up suspect to stand on one toe on a flat-headed peg for one hour on many occasions within a span of a few days.

[20][12] The period between Picton's return and the trial had seen a pamphlet war between the rival camps, and the widespread sale of engravings showing a curious British public what an attractive 14-year-old mulatto girl being trussed up and tortured in a state of semi-undress might look like.

On the evidence presented by the prosecution and with Picton's defence being damaged by the cross-examination of his witnesses ("Mr Bourville was examined relative to the nature of the office of alkald, or justice at Trinidad.

They contained a code expressly applicable to the Spanish West India Islands, and there was not a word about torture in them");[21] the jury decided that it did not and found Picton guilty.

The jury found that torture was authorised by the law of the island at the time of the cession, and that the defendant acted without malice, further than making an order which he thought himself bound to comply with.

Wellington recalled that he had been recommended by General Miranda, who considered him "extremely clever", but also did not trust him, because "he has so much vanity that if you sent him out to the Caraccas or the West India Islands, he would attempt to become the prince of them".

Wellington commented when he met Picton, I found him a rough foul-mouthed devil as ever lived, but he always behaved extremely well; no man could do better in different services I assigned to him, and I saw nothing to confirm what Miranda had said of his ambition.

The commander-in-chief never reposed in him the confidence that he gave to Beresford, Hill and Robert Craufurd but in the resolute, thorough and punctual execution of a well-defined task Picton had no superior in the army.

On the River Coa in July 1810 Craufurd's division became involved in an action, and Picton, his nearest neighbour, refused to support him, as Wellington's direct orders were to avoid an engagement.

In September he was given the local rank of lieutenant-general, and in the same month the division won great glory by its rapid and orderly retirement under severe pressure from the French cavalry at the engagement at El Bodon.

At Badajoz, a month later, the successful storming of the fortress was due to his daring self-reliance and penetration in converting the secondary attack on the castle, delivered by the 3rd Division, into a real one.

According to Picton, the enemy responded by pummeling the 3rd with 40 to 50 cannon and a counter-attack on their right flank (which was still open because they had captured the bridge so quickly) causing the 3rd to lose 1,800 men (over one third of all Allied losses at the battle) as they held their ground.

[28] On 18 June, at Waterloo, when Napoleon sent in the Comte d'Erlon's Corps to attack the Anglo-allied centre near La Haye Sainte at 13:30, Picton launched a bayonet charge on the advancing French column.

[10] Announcing his death, Wellington wrote to the Minister of War, Lord Bathurst: Your Lordship will observe, that such a desperate action could not be fought, and such advantages could not be gained, without great loss; and, I am sorry to add, that ours has been immense.

In Lieutenant-General Sir Thomas Picton, His Majesty has sustained the loss of an Officer who has frequently distinguished himself in his service; and he fell, gloriously leading his division to a charge with bayonets, by which one of the most serious attacks made by the enemy of our position was defeated.

At 6:00 am on 26 June, to the strains of the "Dead March" in Saul, the funeral procession accompanied by the 52nd Regiment of Foot with reversed arms moved off towards London where it arrived on 3 July.