This is a very interesting question, the answer to which opens up some fascinating windows not only into the early history of national intelligence services, but also into our understanding of the historians that study them.

Let's begin, for those unfamiliar with this period, with a brief history of Tsar Paul, son of Catherine the Great, and with the events surrounding his murder.

Paul came to the throne on his mother's death, in 1796. By that time he was 42 years old, married, and had an adult son, Alexander, who was 19. The new Tsar had spent his early adulthood being kept at arm's length from the business of ruling Russia, and the historical consensus is that he proved to be a generally incompetent, capricious and poor-tempered ruler. His foreign policy saw him change sides in the Napoleonic Wars in 1800; having been elected as Grand Master of the Knights Hospitaller in 1798, and been promised that the order's base, Malta, would be handed over to him after the French were expelled from it, the Tsar was enraged when the British reneged on the deal and retained control of the island. In retaliation, Paul expelled the British ambassador to Russia, Charles Whitworth, and allowed himself to be persuaded to drop out of the Second Coalition against Napoleon in favour of joining Prussia and Sweden in the so-called League of Armed Neutrality.

On top of all that, in January 1801 the Tsar committed to an attack on British India, ordering the Don Cossack host to proceed through Khiva and Afghanistan to the Indus, destroy the British armies there, "liberate the oppressed from their overlords, gently bring them under our dependence, and divert their trade to us." Astoundingly, it seems Paul believed that this incredibly ambitious project, conducted in harsh conditions in midwinter, would not only succeed, but could be completed in little more than a month.

So, while it's unclear exactly how much the British knew of the Cossack threat, London certainly had strong reasons for wanting the Tsar off the throne in the weeks and months before Paul's death, and we also know that the British were preparing to take military action against Russia; shortly before Paul’s assassination, a Royal Navy squadron sailed into the Baltic with orders to make for St Petersburg.

Britain was, nonetheless, far from the only enemy that the Tsar had. Some accounts of Paul's foreign policy suggest his withdrawl from the Second Coalition was a product not of British action over Malta, but of his distrust of Austria, which, he feared, was preparing to annex territory in Italy. In addition, the Tsar had as many domestic enemies as one might expect of a ruler who was prone to violent rages and the imposition of severe discipline, and who was also in the process of implementing a number of relatively progressive policies – several of which had the potential to upset elements of Russia's ruling classes. For example, Paul attempted to reduce the burdens of serfdom, clamped down on corruption in the Russian government, and preferred to appoint professional bureaucrats over gentleman place-men in his administration.

The plot to remove the emperor is generally agreed to have been led by the military governor of St Petersburg, Count Pahlen, and approved by the heir to the throne – certainly it's very telling that when Alexander became Tsar, he failed to punish any of the conspirators who had had removed his father. Pahlen assembled a group of discontented nobles and senior army officers, who in March 1801 forced their way into the Tsar's palace, either bearing a pre-prepared abdication document, or at least having the intention to force Paul to write and sign one. When Paul resisted he was strangled and trampled to death.

Historians remain divided as to the motives of the regicides. The consensus, it is fair to say, favours the idea that the assassins were a poorly organised group who were drunk when they burst into the imperial apartments and had no clear idea of how they expected events to pan out, and that Paul's death was not only unintended, but not necessary to their plans. Nonetheless, some evidence has been advanced to suggest that Britain was behind the murder, and that it had been planned in London and co-ordinated by Whitworth. Some of it is merely circumstantial: one of the conspirators, Levin von Bennigsen, was a Hanoverian mercenary, though he was apparently a late addition to the plot, and not apparently one with any significant ties to the British; and James Talbot, who was a close associate of Whitworth's, was apparently relatively close by, in Sweden, in the run-up to the murder. The most widely cited piece of evidence, meanwhile, is a passing mention in a letter of Napoleon's, which darkly accused British spies of being responsible for the murder.

Nothing in the letter, however, suggests that Napoleon had any specific evidence to back up the suggestion. All of which leaves us with the work of Elizabeth Sparrow, whose Historical Journal paper on the UK government's "Alien Office" - set up to monitor foreigners in Britain during the Napoleonic Wars, but, Sparrow claims, later a sort of precursor intelligence agency – and book Secret Service: British Agents in France, 1792-1815 contain the only referenced claims concerning British involvement in the murder of Tsar Paul.

For Sparrow,

it is in the nature of the service that only records of failures were preserved, for the very good reason that they were necessary to protect the individuals concerned... Success must be attributed to conventional warfare or diplomatic treaty and never to the secret service. I have not therefore attempted to include the one great success in the years discussed, but there is reason to believe that the assassination of Paul I was directed from the alien office, almost certainly with the assistance of Calonne [who was a French royalist and the former Minister of Finance to Louis XVI]. There is a paper in the foreign office files which suggests that Lord Whitworth laid the basis of the plan, and the French records unequivocally state that that was so. They also name an agent, Charles-Philippe de Bosset, a Swiss officer from Neuchatel, whose employment by the alien office is well documented, as the man who is believed to have taken the order from London to St Petersburg for the operation to be put into effect.

Unfortunately, Sparrow never quotes directly from the documents she cites - her British archive reference is "Unsigned communication, dated Paris, 13 Mai 1801, P.R.O., F.O. 95" and her French one is "Jean Tulard, 'Whitworth, Sir Charles', Dictionnaire Napoleon (Paris, 1987), p. 1750; Constantin de Grunwald, L'Assassinat de Paul 1er Tsar de Russie (Paris, 1960), pp. 174-5", so it's impossible to say with any certainty whether they are actually as incriminating as she suggests. It's worth pointing out that few academics have followed her lead, with the exception of William R. Nester, a professor of political science at St John's, Newfoundland, whose book on British power in the period not only follows Sparrow (without citing any additional evidence), but rather surprisingly uses her work to allege that

circumstantial evidence links the Alien Office to such "wet operations" as the attempted murder of Napoleon Bonaparte in 1800 and actual murder of Tsar Paul in 1801.

It certainly does seem to be the case that there was sufficient discontent within senior circles in St Petersburg to make it relatively unsurprising that Paul was deposed, and that British intervention would not have been required to bring about this result. Similarly, the half-organised, semi-farcical assassination that actually occurred was not the sort of plot that could only ever have been brought to fruition with foreign help; it was also scarcely something that required "funding," and no one has produced evidence that the British had any reason to be certain that Paul's son Alexander would return Russia to the coalition fold, which he eventually did – rather than carry on with his father's attempts to invade India, which Napoleon certainly encouraged him to do. Conversely, it is possible to make the argument that Sparrow, like other intelligence historians, is prone to exaggerate the influence and impact of secret service operations, and also true that her depiction of the Alien Office as a ruthless and efficient proto-SOE hardly squares with the amateurish, uncertain, thuggish murder that actually took place in St Petersburg in March 1801 - a conspiracy that, inter alia, involved the leader of the plot and half his men getting so lost in the palace gardens that they did not arrive until after the emperor was dead. And, very definitely, the British did not have the capacity, in 1801, to assassinate the Tsar without significant co-operation from a large number of the most senior figures in the Russian state.

Finally, I should point out that Sparrow was not a professional historian, and came to her study of the Alien Office via an unusual path – so, while she deserves praise for her diligent and imaginative research methods, it is permissible to wonder whether her accounts are as cautious as would be considered ideal for an historian of this rather complex period of history. Certainly I, reading her stuff, thought it involved quite a lot of unproven assumptions and was terrible at placing the activities of the Alien Office within the broader context of British strategy and aims in the Napoleonic period.