There are many theories about the nature and identity of Spring-heeled Jack. This urban legend was very popular in its time, due to the tales of his bizarre appearance and ability to make extraordinary leaps, to the point that he became the topic of several works of fiction.
Spring-heeled Jack was described by people who claimed to have seen him as having a terrifying and frightful appearance, with diabolical physiognomy, clawed hands, and eyes that "resembled red balls of fire". One report claimed that, beneath a black cloak, he wore a helmet and a tight-fitting white garment like an oilskin. Many stories also mention a "Devil-like" aspect. Others said he was tall and thin, with the appearance of a gentleman. Several reports mention that he could breathe out blue and white flames and that he wore sharp metallic claws at his fingertips. At least two people claimed that he was able to speak comprehensible English.
The Times reported the alleged attack on Jane Alsop on 2 March 1838 under the heading "The Late Outrage At Old Ford". This was followed with an account of the trial of one Thomas Millbank, who, immediately after the reported attack on Jane Alsop, had boasted in the Morgan's Arms that he was Spring-heeled Jack. He was arrested and tried at Lambeth Street court. The arresting officer was James Lea, who had earlier arrested William Corder, the Red Barn Murderer. Millbank had been wearing white overalls and a greatcoat, which he dropped outside the house, and the candle he dropped was also found. He escaped conviction only because Jane Alsop insisted her attacker had breathed fire, and Millbank admitted he could do no such thing. Most of the other accounts were written long after the date; contemporary newspapers do not mention them.
After these incidents, Spring-heeled Jack became one of the most popular characters of the period. His alleged exploits were reported in the newspapers and became the subject of several penny dreadfuls and plays performed in the cheap theatres that abounded at the time. The devil was even renamed "Spring-heeled Jack" in some Punch and Judy shows, as recounted by Henry Mayhew in his London Labour and the London Poor:
"This here is Satan,-we might say the devil, but that ain't right, and gennelfolks don't like such words. He is now commonly called 'Spring-heeled Jack;' or the 'Rossian Bear,' - that's since the war."
—Henry Mayhew, London Labour and the London Poor, p. 52
But, even as his fame was growing, reports of Spring-heeled Jack's appearances became less frequent if more widespread. In 1843, however, a wave of sightings swept the country again. A report from Northamptonshire described him as "the very image of the Devil himself, with horns and eyes of flame", and in East Anglia reports of attacks on drivers of mail coaches became common. In July 1847 'a Spring-heeled Jack investigation' in Teighnmouth, Devon led to a Captain Finch being convicted of two charges of assault against women during which he is said to have been 'disguised in a skin coat, which had the appearance of bullock's hide, skullcap, horns and mask'. The legend was linked with the phenomenon of the "Devil's Footprints" which appeared in Devon in February 1855
