Alerted by a barking sniffer dog, the officers wrench off a wooden wall panel to find a secret compartment full of illegal tobacco.

In another room, they pull at an electric radiator, which gives way to reveal another hidden chamber used to stash black market goods.

Dodgy shops selling counterfeit items, employing trafficked workers or washing dirty money for crime gangs are a common feature of British high streets. 

But while red flags like cash-only policies, unusually low prices and a lack of customers are fairly easy to spot, uncovering the full truth is far more difficult.

Owners of dodgy shops are attempting to evade police and council officials by installing increasingly elaborate 'hides' to store illegal goods and dirty cash.

Many are installed by dedicated specialists and secured by electro-magnetic locks that are switched on and off using remote controls, switches or key fobs.

The Daily Mail saw three hides being exposed during an operation targeting convenience stores, nail salons, barbers and massage parlours in Lowestoft, Suffolk. 

Part of Operation Machinize – a UK-wide crackdown on high street crime led by the National Crime Agency (NCA) – the raids involved officers from Suffolk Police, Immigration Enforcement and Trading Standards.

Security minister Dan Jarvis watched on as specialist teams equipped with a sniffer dog targeted around ten stores that had been identified as potentially linked to crime.

The first raid was on a vape shop, where a door disguised as shelving led into a back room lined by plywood panels.

After a sniffer dog trained to identify tobacco and cash picked up a scent high up on one of the walls, officers removed a panel to reveal a set of shelves attached to a sliding mechanism that allowed them to be pushed up into a void in the ceiling.

Inside was a stash of illegal and counterfeit tobacco worth £1,000 that was ready to be sold to customers at a lower price than legitimate brands. 

The second hide – behind a radiator – was found nearby but was empty. 

At another shop nearby, officers found a compartment around 2ft wide and 3ft deep under the shop floor.

Officers also raided a brothel, where they arrested two people for modern slavery and immigration offences.

Following the raids, Mr Jarvis told the Daily Mail: 'The use of shops for criminal activity is an issue we've known about for a while, with some of these premises effectively hiding in plain sight. 

'That's why we're targeting these illicit shops to stop them taking root on our high streets and harming legitimate businesses that have to compete with them.' 

The Home Office has announced the recruitment of 500 new officers to counter money laundering networks across the UK as part of a £500million investment over three years. 

These officers will be deployed to police forces, the NCA and the Crown Prosecution Service (CPS) to 'go after the kingpins' who launder an estimated £1billion through the UK economy each year. 

Many dodgy shops have illegal goods seized from them but are able to remain open for business. Councils are currently only able to close premises for six months but the Government is doubling this to a year. 

Mr Jarvis added: 'It's really important that enforcement action is taken against shops involved in criminal activity.

'We're working with local authorities to ensure they understand and use the powers that are available to them.' 

Police say individual shops can make as much as £3,000 a week selling illegal tobacco. 

This starves the Treasury of tax revenue, while funnelling money to gangs involved in a wide variety of other criminal businesses. 

John French, a modern slavery specialist at Suffolk Constabulary, said dodgy shops were often linked to organised immigration crime. 

'The shop workers will often be exploited or forced to work under threats of violence against them or their families,' he said. 

'It's very easy to say that these people are working for the business owners by choice and could get away if they wanted to, but often there are good reasons why they can't.' 

MP for Lowestoft Jess Asato said: 'Our hardworking local traders follow the rules, and they rightly expect others to do the same. 

'Those who break the law must face the consequences.'