One of the most bloody and notorious episodes in Weymouth’s history will be remembered and replayed next weekend.

And while the streets may not run with blood, nor the harbour be blocked by the floating bodies of Irish mercenaries, anyone visiting the town should prepare to be caught up in the occasional skirmish and witness a hanging or two.

From February 14 to 16, hundreds of historic re-enactors will be descending on Weymouth to recreate the Crabchurch Conspiracy, a little-known but vitally important English Civil War battle.

The Conspiracy, which rumbled on for most of February 1645, was a Royalist plot hatched by Fabian Hodder to bring Weymouth and Melcombe under control of the king’s forces.

At its height, it was a desperate and bloody battle, with both sides gaining the upper hand at various times.

The Parliamentarians were up against a much larger Royalist force but eventually the much smaller Roundhead army won the day under Colonel William Sydenham, whose brother Francis, ‘a real Errol Flynn character’, died in the battle.

Among the casualties were 250 Irish mercenaries whose bodies were piled up in ‘Weymouth Hole’, an inlet where Hope Square now stands. And it is said that their ghosts can be heard crying out to this day . . .

Historian Mark Vine, who has written the definitive book on the Crabchurch Conspiracy, said: “Five hundred people were killed during the battle in Weymouth – that’s more than died in some of the ‘major’ battles during the Civil War.

"The king, Charles I, wanted a safe south coast port so he could land a large French army so he chose Weymouth. But Sydenham, whose forces were out-numbered by six to one and who faced almost certain defeat, fought the king’s forces and won a marvellous victory.

"If he had lost, the course of our history could have been very different. It would have changed everything and we could be speaking French today!”

On Saturday, Parliamentarians and Royalists will square up and battle it out on Weymouth beach with musket and pike. The contingency plan, should the weather fail, is that a number of pubs will take part in a series of ‘arrests’ and skirmishes throughout the day