Partygoers in Shoreditch are being tricked into handing over as much as £500 a pop for paracetamol by groups pretending they are selling cocaine, the Gazette can reveal.

A suspected scammer was questioned after buying a box of the painkillers in a convenience store in Old Street on Friday night, believed to be one of a gang of about 30 who police said had been “terrorising the area” this year – starting fights, harassing women and trying to pass off over-the-counter painkillers as class A substances.

Pc Shaz Ahmed told the Gazette: “They are only offering to supply paracetamol, which isn’t an offence so it often goes nowhere.

“They will say: ‘Do you want coke?’ All the drunk people are doing is snorting paracetamol up their noses. They might not have a hangover the next day, though.”

Sgt Mark Page described how lone drunken men stumbling to a bus stop might become targets.

“He will get surrounded by a group. One will come up and say: ‘Are you ok? Would you like some drugs?’

“Which it isn’t. It’s paracetamol.”

The “victim” might agree to buy coke – but when they snort a sample and realise it isn’t cocaine, they might be surrounded by six men demanding payment anyway.

“They’ll say: ‘It’s £50 or we are going to kick the stuffing out of you.’

“He will be frogmarched to a cashpoint and they’ll take £500.”