Liverpool and North West gangs 'dominate' UK guns and drugs trade
Nearly three-quarters of secret communications about guns between crime gangs had links to Liverpool and the north-west of England, police said.
Nearly 750 people were arrested and guns and drugs seized after detectives cracked the EncroChat system.
Messages revealed that organised crime gangs in Liverpool "dominate" the UK's guns and drugs trade outside London, said the National Crime Agency.
Cocaine is also being smuggled direct from South America into Liverpool.
More than two tonnes of drugs, several dozen guns and £54m in suspect cash have been seized.
Officers from the NCA's National Firearms Threat Centre (NFTC) found 70% of all links to weapons examined in that operation led to Liverpool, Manchester and surrounding areas of the North West.
Rob Hickinbottom, lead on the NFTC, told The Observer: "Most of the cases have a very strong connection to the North West."
The NFTC found that a low-calibre Glock hand gun bought for £136 in eastern Europe could be converted in just 90 seconds to a 9mm weapon to be sold for £5,000.
All that was needed was a £3.50 plastic switch imported from China.
Gangsters were also converting low-calibre weapons into automatic guns.
Matt Perfect, the firearms threat lead for the NCA, said: "The evidence is that the North West groups pretty much dominate the rest of the [criminal] communities in the UK."
He said gangs in Liverpool have benefited from the city's geography with links to the sea, Ireland, Scotland and "gun capital of Manchester".
The city also has big crime figures such as Curtis Warren, 57, from Toxteth, who was once Interpol's most wanted drug trafficker.
Merseyside Police have arrested 30 people over the past month as part of the crackdown on organised crime.
Officers have recovered more than £2m in cash, three firearms and ammunition as well as 25 kilos of Class A drugs.
They also found 450 cannabis plants, 28 kilos of Class B drugs and 1.5 tonnes of mixing agents.
Why not follow BBC North West on Facebook, Twitter and Instagram? You can also send story ideas to [email protected]