The most obvious enemy force for his army to engage was the army of Marshal Marmont. The latest intelligence suggested that Marmont commanded fewer than thirty-five thousand men, and that decided Arthur.

Early in May, he left General Hill and eighteen thousand men at Badajoz, in case Soult decided to venture out of Andalucia, and marched back to Ciudad Rodrigo to organise his offensive against Marmont. As he waited for the final reinforcements to reach him from Oporto, he gave orders for his wagons to be repaired and loaded with marching rations from the fortress’s depot. The soldiers were rested, and given the chance to repair their kit in readiness for the campaign.

Late in the month, as Arthur was putting the final touches to the campaign plan, Somerset entered his office with the latest packet of despatches from London.

‘Left London on the twelfth. They’ve made good time,’ Arthur noted with satisfaction. He broke the seal, opened out the waterproofed covering and extracted the documents within. At the top of the pile was a small note from Lord Liverpool marked Most urgent - read at once.

Arthur raised his eyebrows, then with a slight shrug he pushed the rest of the letters towards Somerset. ‘Prioritise those for me, if you please.’

His aide nodded, pulled up a chair and began to open and sort through the documents, ensuring, as was customary, that personal and administrative missives were placed below more vital communications. Arthur sat back in his chair and broke the wafer seal on Liverpool’s letter, unfolded it and began to read. At length he folded the letter up.

‘The Prime Minister is dead,’ he announced evenly.

Somerset looked up from the latest document he had been glancing through. ‘I’m sorry, my lord, I missed that.’

‘I said the Prime Minister is dead.’

‘Good God. Dead? How? Accident or illness?’

‘Neither. He was assassinated. Shot in the lobby of the House of Commons. Some madman named Bellingham who blamed Perceval and the government for ruining his business, apparently.’

‘I say, that’s a bit much.’

Arthur raised his eyebrows. ‘ “A bit much” is hardly the apposite reaction, Somerset. The man has deprived us of a Prime Minister.’

‘Sorry, sir. I’m just shocked by the news. It’s not the sort of thing that happens in England. France or Russia yes. But England?’