One man was conned of cash and his £29,000 Rolex watch outside the Ritz Hotel in central London.
Andrew Gordon, 57, denied three counts of fraud when he appeared at Westminster Magistrates Court on December 22.
The court heard he scammed one man out of more than £5,000, initially withdrawn in euros before being converted into pounds, in March this year.
On the same day he is said to have conned another man out of £6,500 in cash which he persuaded the victim to withdraw, and a Rolex worth £29,350 as he lurked outside the swanky Ritz Hotel in Central London.
He is also accused of calling an elderly woman and impersonating West Yorkshire Police to scam her out of £5,000 in June last year.
Prosecutor Jordan Pratt said: "This was three separate acts of fraud against elderly victims who the defendant stole from by acting as a police officer. He persuaded them to hand over expensive and high value items, and sometimes money as well.
"He persuaded his first victim to hand over more than £5,000 in euros which he converted into pounds; the second victim had £6,500 stolen from his card as well as a £29,350 Rolex watch.
"Both offences took place on 13 March 2021 in London's West End, and the second victim was defrauded outside the Ritz.
"He called his third victim on 25 June last year and pretended to be West Yorkshire Police before defrauding her out of £5,000. This case is not suitable for summary trial."
Appearing via video link from HM Prison Durham, Gordon spoke only to confirm his name, date of birth and address and to enter not guilty pleas to three counts of fraud during the ten-minute hearing.
Dressed in grey prison uniform, he showed little emotion as he entered his pleas.
An application made by his lawyer Syed Ahmed to grant him bail was rejected by magistrates.
He will next appear at Southwark Crown Court on 19 January for a case management hearing.
Chairman of the bench Andrew McMurtirie said: "Our sentencing powers are insufficient, and we are of the view he should be remanded into custody."