Chris Lloyd concludes his Christmas ghost story with a brutal murder and offers a few facts that may convince you that the ghost really did exist.

Bishop John Cosin had a troublesome brood of children. His daughter, Lady Burton, ruined her reputation in an ale-house in Westmoreland, an incident the Bishop drew a discrete veil over as he wrote her out of his will.

His only son, John, heaped further shame upon him by twice converting to Catholicism - the ultimate indignity for the Protestant Bishop of Durham. No number of entreaties could persuade John of the true path of enlightenment and he was last heard of living in a convent in Paris.

Naturally, his two remaining daughters, Mary and Frances, were the apples of the Bishop's eye and during the troubled days of the Commonwealth, when the Bishopric of Durham had many of its treasures stolen from it, he restored the Bishop's Palace on the banks of the River Skerne in Darlington as his family's sanctuary.

There lived his eldest daughter Mary who married Sir Gilbert Jarratt (or Gerrard) of Lincolnshire. Sir Gilbert was a man of some substance. He was the Sheriff of Durham, and had been the Constable of Durham Castle, until Cromwell had confiscated it from the Bishop. Now he was rebuilding his career, and plotting to become MP for Northallerton.

Sir Gilbert was also a man of some retinue: his younger brother Sir Charles, for instance, came with him to the Bishop's Palace and was appointed the Bishop's housekeeper and bailiff of Coatham Mundeville. To keep everything in the family, Sir Charles married Frances, Bishop John's other daughter.

So there were at least two Lady Jarratts living in the Bishop's Palace around 1668: Dame Mary and Dame Frances. There may even have been more, as Sir Gilbert's spinster sisters or maiden aunts would also have gone by the same title.

And the story that was racing through Robert Luck's mind 200 years later after he'd felt the breath of a lady, and the silk of her skirt, when he was alone in the old palace chip, chip, chipping away at that now derelict Bishop's Palace, concerned the brutal murder of a Lady Jarratt.

The Lady Jarratt of the story was a creature of habit, every night enjoying a gentle turn along the sylvan banks of the Skerne, taking in the evening air, before retiring.

On the night of the story, she was unattended in the Palace - the Cosins and the Jarratts were all away on business or pleasure. But on this night, she was not unnoticed. In these troubled times, troops of all causes - and none - roamed the North-East, and on this night two soldiers followed every step of her genteel routine from a hiding place. Then, when she returned to the Palace, they followed her inside, too.

Past the medieval arches she walked in her long white silk dress on her way to her bed; up the grand sweeping staircase and along the echoing corridor to her chamber. They followed, and then pounced.

In her bedchamber overlooking the Skerne - possibly the room in which Queen Margaret, the daughter of Henry VII and the grandmother of Mary, Queen of Scots, had stayed in 1503 - they demanded money. Lady Jarratt protested that she had none.

The more she protested, the more belligerent the soldiers' demands became; they began jostling her; she tried to flee. Along the corridor she ran, crying out for assistance.

They caught her at the top of the staircase, trying to silence her screams. Still she protested that she had no money - but they had seen the rich jewel-encrusted ring on her finger. They pulled at it, they wrenched at it, but it would not come off.

Lady Jarratt became more frantic and the soldiers became more desperate. Down the stairs they tumbled, a threesome in a frenzy, the lady in her finery fighting for her life and her property, the soldiers in their uniforms determined that she should submit.

As they hit the bottom, there were stirrings elsewhere in the Palace. Her alarm had been heard, and the Bishop's men were coming to her rescue. The soldiers would have to be quick. But still the ring wouldn't come.

One of them pulled out his knife. If he couldn't have the ring, he would have the whole arm. With a couple of butcherous blows, he was through, and the pair of them were off down the corridor with their bloody prize.

They were never seen again, although about a week later, a fisherman in the Skerne hooked a gruesome catch when he pulled out a severed limb minus, of course, its rich adornments.

Lady Jarratt sunk to her knees, her wound bleeding heavily - fatally. As she slid down the wall, she left a trail of red down the whitewash, culminating in a pool on the floor, as a record in blood of her very last movement.

In the years, decades and centuries afterwards, Lady Jarratt became Darlington's favourite phantom as she glided over the Skerne and spirited her way down Leadyard, always crying, and always apparently searching for her missing arm.

The servants in the palace, and then the maintenance men in the workhouse, tried without success to erase the bloody stain that Lady Jarratt had left in the moment of her murder. But, no matter how much paint they applied, it always re-appeared, a gruesome reminder of a heinous crime.

Her blood was sprinkled upon the floor;

On the wall is the mark of her fingers four,

And her thumb, in blood, as she dying lay,

And they strove in vain to snatch away

A ring of price from her swollen hand.

In haste to go were the murderous band

So they hewed off her arm, and then fled full fast,

With the costly ring as their prize at last.

The stains are there, they will not away

Where the blood is spilt, must the spirit stay.

Robert Luck knew all this as, 200 years later, he started chip chipping away at the whitewash on the medieval arch near the foot of the stairs. "I suppose that my experience of Lady J must have arisen from my unconsciously thinking about her in some way," he wrote early in the 20th Century.

He could also explain away the stain. "When the building was pulled down, I found the stain in the floor, which was lime and gravel, was caused by some of the red sandstone which is found in the Skerne and the Tees, and which had been crushed," he wrote.

But the experience was not enough to stop the Lucks removing the 'haunted' arches to their garden in Middleton St George, although the one from the foot of the stairs remained in the Leadyard until the 1930s when it was supposedly taken to South Park. Today, the entrance to the grotto beneath the clocktower is through a curved archway. Since the new Town Hall was built on the site of the Leadyard in 1970, there have been so few sightings of Lady Jarratt that we can safely say that she is now resting in peace.

Indeed, in our 21st Century certainties, we can say that she never existed at all. We've never known precisely who she was - the many versions of this tale all suggest that Lady Jarratt was Dame Mary, the Bishop's eldest daughter, but we know she was still happily married to Sir Gilbert and bore him a child after 1671 - years after the brutal murder was supposed to have taken place.

So perhaps we should dismiss the story of the ghost of Lady Jarratt as just another spooky tale from the days before electricity when flickering candles and wavering gas lights threw all types of spectres into dark corners for the over-imaginative to believe in.

But before we leave her, let us once more look at the history books. Let us look at Bishop Cosin's notoriously troublesome brood of children: Lady Burton who ruined her reputation in an ale-house, and son John who ruined his father's reputation by ending up in a Catholic convent in Paris.

Dame Mary was the apple of the Bishop's eye - in the year of the supposed murder, he granted her the Manor of Chilton for her personal use.

But what of Dame Frances? When her husband, Sir Charles Jarratt, died she took up with an untitled Darlingtonian called Thomas Blakiston and began styling herself as his wife.

Bishop John was not at all happy with such a lowly, disreputable carry-on. There's a letter of his, dated March 19, 1668, in which he writes full of fury: "You mention my daughter as the wife of TB which I have not yet acknowledged, nor was it ever made knowne to mee that they were legally married and whensoever it shall be so made known, I must professe beforehand that I am extreamly displeased with it, for I was most treacherously used above and for my part shall never owne it."

The letter shows that Bishop John is fighting Frances' "pretended new husband TB" who is stealing away the inheritance rightfully reserved for Sir Charles' children. Having ignominiously lost one daughter to an ale-house and a son to a convent, the dastardly TB was also stealing away with what remained of the Bishop's reputation. How did Bishop John react?

And what of Sir Gilbert, brother of the late Sir Charles? He had thrown his lot in with the Bishop, coming from Lincolnshire to marry Dame Mary. Now, with his brother dead, could he see the gold-digging TB making off with money that would have come to him as the husband of Dame Mary, the only remaining beneficiary in Bishop John's will? How did he react?

Could the Bishop and the Knight, together or alone, have arranged a murderous fight - which could be dismissed as yet another sign of the murderous times when even anointed kings lost their heads - when they knew that the errant Lady J would be unattended?

It would have solved many of their problems.

Sadly, the history books don't tell us. But, curiously, the one hard fact that they do leave us with is that Dame Frances, "wife of Thomas Blakiston" was buried at St Cuthbert's Church, Darlington, on March 10, 1669.

The churchyard is just a few yards from the Palace where Lady Jarratt was so brutally murdered, just a few yards from where her blood stained the walls for centuries to come, and just a few yards from where her ghost roamed in search of her severed arm. And it was exactly 200 years, possibly even to the day, when Robert Luck was chip, chip, chipping away at the whitewash on the arch at the foot of the stairs where she fell in the moment of her murder.

And the Lady Jarratt still wanders there,

Where she dwelt in life is she doomed to fare

In death. One arm is clear to see,

Empty the sleeve where the other should be.