The dispute sits at the centre of the long-running Undercover Policing Inquiry (UCPI), which is examining the activities of the Met's Special Demonstration Squad (SDS).
Coles, 66, is the brother of broadcaster Reverend Richard Coles and is active in local Conservative politics. He infiltrated the Animal Liberation Front under the name Andy Davey, an identity taken from a dead child. He has said the qualities needed in a good undercover officer included resilience, bravery and ruthlessness. Asked if that included a skill for deception, he replied: 'I suppose so. Though I didn't behave very differently to my own personality.'
Jessica, now 54, told the BBC she was 19 and living in a shared house in east London when she met Davey in 1991. She remembers him as an awkward older man who drove a van and who she struggled to get rid of late at night. She says he became her first proper boyfriend. 'He groomed me,' she said. 'He would sleep in my single bed several times a week, and I didn't know who he really was.' She has provided handwritten letters from 1993 which allude to the relationship. A forensic graphologist told the BBC her handwriting appeared to vary but it was possible she wrote both letters at around the same time.
Coles has admitted sharing Jessica's bed on one occasion but says there was never any sexual contact. He told the BBC the claims against him are fabricated. 'It's payback, pure and simple,' he said. 'Her story is not true, absolutely not true.' He has theorised that a second letter submitted as evidence was written much later and added to the evidence bundle, describing the handwriting as an elegant cursive compared to her earlier childlike scrawl.
The Met's commissioner, Sir Mark Rowley, has written that the force accepts Coles had a sexual relationship with Jessica and is disappointed he did not tell the truth to the inquiry. The commissioner's statement contrasts with Coles's insistence that witnesses against him are seeking revenge. 'It's hardly surprising they'd want to get their own back on me,' he added.