It is arguably the greatest ‘what if’ in Scottish history and it happened in this week of 1745. In this 275th anniversary of the ’45, we can again ask the question “what if Bonnie Prince Charlie and his army had not stopped at Derby and had kept on marching to London?”

If you can find a copy, the best account of the ’45 is by David Daiches in his magisterial Charles Edward Stuart: The Life and Times of Bonnie Prince published in 1973. This column draws heavily on Daiches’s book and the original contemporary accounts of the campaign by Charles’s officers Chevalier James de Johnstone, Lord George Murray and Sir John O’Sullivan.

It is important to note that Charles always intended to invade England. His march south from Glenfinnan to Edinburgh had been quick and decisive but had not gathered the forces he thought he would gain. Promised French support also failed to materialise, though King Louis XV eventually did deliver some arms and money. Charles also needed time for his army, comprised mainly of Highlanders, to regroup, and on September 17, they marched unopposed into Edinburgh where only the castle remained in Hanoverian Government hands.

The Government’s army in Scotland was led by General Sir John Cope, who was inexperienced in command and whose troops were mainly conscripts. Cope knew he had a larger force and that the Jacobite army was poorly armed. It was a highly committed Jacobite army, however, and on the morning of September 21, 1745, with one devastating Highland charge, fewer than 2,000 Jacobites smashed through the Government army of 3,000 men, killing around 400, capturing 700 and sending the remainder fleeing down the coast – including Cope. The Jacobites lost between 70 and 80 of their force – it was a total victory, the news of which stunned Scotland, England and beyond.

Apart from garrisons at Dumbarton, Stirling and Edinburgh Castles, the Prince was master of all Scotland. Lord George Murray had organised the usually unruly Highlanders into a proper army and the Prince’s command was enough to raise considerable sums of money from Scotland’s burghs to keep that army paid.

There was the famous period in Edinburgh where James Stuart was acclaimed King and Charles named Prince Regent and balls were held to celebrate the return of the Stuarts, but Charles wanted the throne in London and that meant invading England.

He now had a war council and they met on October 30 to devise a clever plan. They knew they were facing a hugely increasing Government army which had been hastily withdrawn from the Continent where they were fighting in the War of the Austrian Succession, but that army was split into three – one based at Newcastle under Field Marshal Wade, a second army under General Sir John Ligonier in Lancashire and a third army on the south coast, King George II fearing an invasion by the French.

Charles split his army in two but it was only a feint to convince Wade to attack, and meanwhile the bulk of the force went down the western route and took Carlisle with ease. There he and Lord George Murray fell out over the strategy and Murray resigned as field general only to be reinstated days later – the Prince and the general were never on the same page again.

Down through England they marched, and the further south they went, the more the relationship between Charles and Murray deteriorated. The Prince’s mood was not helped by the fact that the anticipated recruitment of Jacobites in the North of England did not happen to any great extent. Only in Manchester did around 200 to 300 men join up for service, and some of these Jacobites would later pay a very heavy price for doing do, at least a dozen of them being hanged, drawn and quartered as traitors at the express command of King George II.

By December 4, there had already been numerous discussions in the Prince’s Council about whether to march on or return to Scotland. An unknown number of Highlanders had already made up their own minds and gone home, and as they entered Derby the Jacobite Army was probably down to under 5,000 men, mostly all foot soldiers.

They were still a formidable force and though rumours of their savagery were greatly exaggerated, entire English towns quailed at their approach. In London, an army of volunteers met up at Finchley Common but no one doubted that they would run away from a Highland charge. George II prepared his household to evacuate, but all the time Wade and his forces were moving from the east and the western Government army, now under the command of the battle-hardened Duke of Cumberland was due south of the Jacobite march and preparing for battle.

Charles wanted to march on London with alacrity but Murray and the rest of the Council knew they were eventually going to face overwhelming numbers and they advised retreat to Scotland. An advanced guard was sent to Swarkstone Bridge six miles south of Derby and just 110 miles from the centre of London. It was the furthest point that the Jacobite army reached in its invasion of England.

What if the Council had listened to Charles and marched swiftly to London? They could have avoided Cumberland’s army and smashed the London militia, forcing George II to flee. Furthermore Charles’s brother Henry had finally assembled a force of 10,000 trained French soldiers at Dunkirk and was awaiting word to invade across the Channel. Yet it all went wrong, and the trail north to Culloden and catastrophe began on December 5, 1745.

Daiches wrote: “There is reason to believe that if Charles had had his way and pushed on by forced marches to London he might well have succeeded in bringing about a Stuart restoration.”