Who is Lisa Johnson? That was question that left a courtroom baffled.

To Willesborough chartered accountant Brian Ridpath, she was a “damsel in distress” who needed rescuing from a corrupt regime in Nigeria.

To his close pal, Christopher Rundle, she was a sewing machine importer and business associate of Ridpath who needed emergency funds.

But to police officers and a judge, Lisa Johnson – if she really exists – was a woman who used her sex appeal to dupe the 79-year-old Ridpath into sending her £150,000 of his friend's money.

Now the churchgoing and well-respected professional has lost his good reputation, his friend, his home - and now his freedom.

Ridpath, of Cornes Close told lies to business pal Mr Rundle to persuade him into lending cash with a promise it would be repaid by Lisa Johnson within days.

Finally, following a year of prevarication after the scam was revealed, the accountant was asked directly by Judge Simon James: “Has he ever met this woman - yes or no?”

Ridpath, who cut a sad figure in the dock at Canterbury Crown Court, whispered to his lawyer who told the judge: “No. Only in the sense of having met online.”

But even as police were probing the disappearance of the money, Ridpath believed in her existence and stories about hundreds of thousands of dollars in Nigerian bank accounts.

As his former friend was trying to recoup the missing funds, Ridpath was secretly sending her more money from another bank account.

And he was only prevented from sending the entire proceeds from the sale of his home by an injunction, the court heard.

Prosecutor Iestyn Morgan said it was accepted that Ridpath, who is single, had not benefited from the fraud – which he admitted only on the day his trial was due to start.

He told how November 2014 the accountant – who had done Mr Rundel’s VAT returns – asked to meet his friend.

Ridpath told of his business relationship with Lisa Johnson who was working in Nigeria and needed £30,000 and had $640,000 awaiting from a deal with China.

He said the two had met in Liverpool and he assured his friend she had the money to repay.

"That individual's sexuality was cynically employed to encourage you to throw away all good sense and led you to deceive a business associate and friend" - Judge Simon James

But days later, the accountant asked for another loan of £90,000, and then another £30,000.

Mr Morgan said that “Lisa Johnson” had even sent emails to Mr Rundle with tales of her passport being seized, hotel bills needing settling.

He said by November 16, Ridpath told his friend that Ms Johnson was still in Nigeria and needed yet another £35,000, but Mr Rundle refused and the police were alerted.

When officers went through the accountant’s computer, they discovered sexual pictures of a woman calling herself Lisa Johnson.

“The indecent photographs showed her to have been more than just a business partner," added the prosecutor.

Guy Wyatt, defending, said defence lawyers were still receiving emails from “Lisa Johnson” and that Ridpath still believes in her existence.

He added: “Your honour may think it’s an unfounded belief, a bizarre belief. But if she really is in Nigeria and in trouble, having fallen prey to the corruption regime, then his attempts to help her, although flawed, were humanitarian.

“Or he is the sad and foolish victim about the oldest fraud known to man and perpetrated against an elderly single man but he really believes he was helping a damsel in distress.”

The judge jailed Ridpath for 18 months, saying: “I don’t know whether you are deluded or have been totally taken in.

“This offence was initially borne out by a combination of naivety and exploitation. It is clear to me if not to you, that you were targeted by fraudsters who used you quite cynically.

“But so complete were your delusions you became blinded to the fact that you were being manipulated after becoming fixated by a woman half your age who you had never met.

“That individual’s sexuality was cynically employed to encourage you to throw away all good sense and led you to deceive a business associate and friend.”

He added that it must be humiliating for a chartered account to have to admit “not only to crass stupidity but also dishonesty” which had left him penniless.

After the hearing, Detective Constable Geoffrey Kirya who investigated the case said: "The defendant denied any wrongdoing throughout the investigation.

"It was a long and thorough investigation which involved trawling through thousands of emails.

"We eventually found the evidence that proved that the defendant lied to the victim that he knew the person in Nigeria.

"I am pleased with the outcome which serves as a warning that crime does not pay. It should also serve as a warning to others that fraudsters come in all forms including people in position of trust."