Police and special forces are fighting a cat and mouse game against the scourge of cartel 'mother ships', which circle Britain laden with cocaine before throwing their hauls overboard so they can be picked up by smugglers. 

The National Crime Agency (NCA) says tens of millions of pounds worth of drugs are being trafficked into Britain using the method - and are urging coastal communities to be on high alert. 

The tactic involves South American cartels stashing drugs on container ships heading to Europe so they can approach British waters without attracting attention. 

Bales of drugs attached to flotation devices fitted with trackers are then ditched into the water, before local smuggling gangs come out to find them. 

In response, the NCA and Border Force are urging people living along the coast to report any suspicious sightings of small boats in harbours, coves or beaches. 

As well as intercepting the boats themselves using cutters, civilian law enforcement can also call on special forces units,  such as the Royal Navy's Special Boat Service (SBS).  

In one particularly dramatic operation that came to light last month, a squad of soldiers from Ireland's elite Army Range Wing fast-roped from a helicopter onto a 'narco tanker' in the Irish Sea.

The high-stakes mission followed an undercover operation by the US Drug Enforcement Administration (DEA), which penetrated a global drugs trafficking ring run by the Kinahan cartel. 

More than two tonnes of cocaine worth £132million - the biggest seizure in Irish history - was recovered from the MV Matthew, a Panamanian cargo ship, with eight men arrested. 

They were sentenced on July 4, allowing the operation to be described in full detail.

The warnings from British officials follow the jailing of four men for their part in a plot to bring £18million of cocaine into the UK after picking it up off the coast of Cornwall. 

The method of jettisoning drugs from a mother ship before they are picked up by smaller craft is known as the 'at-sea drop-off' (ASDO) method. 

Three of the men tried to outrun Border Force for 28 miles at sea after their boat was spotted picking up drugs off the coast of Newquay.  

They eventually ran ashore at Gwynver beach near Sennen and - alongside two co-conspirators - were jailed last week at Truro Crown Court for a combined total of 82 years.

Another gang were arrested in September accused of picking up a tonne of cocaine near the Isles of Scilly - part of £540million intercepted last year by gangs using ASDOs. 

The National Crime Agency (NCA) told MailOnline the use of mother ships had become increasingly common.

The agency explained gangs typically relied on a corrupt crew member or stowaway onboard commercial vessels travelling to Europe from South America or West Africa. 

'Once in UK seas, the stowaway or crew member drops bales of cocaine overboard with a flotation device and tracker,' a spokesman said. 

'The illicit cargo is collected at sea by UK-based criminals in small fishing boats or rigid-hull inflatable boats (RHIBs).'

The NCA has launched 60 investigations into ASDO incidents last year, resulting in the seizure of nearly five tonnes of cocaine, 34 arrests and prison sentences totalling more than 226 years. 

'Our work doesn't stop at seizing cocaine and arresting smugglers in the UK – we're also working with international partners to identify and pursue those involved in dropping off the drugs,' the spokesman added. 

ASDOs usually take place near Cornwall but have also happened in the Irish Sea and North Sea. 

The UK coastline stretches more than 11,000 miles, with numerous coves, harbours and sheltered beaches where smugglers can land cargo with less chance of detection. 

Border Force's maritime unit has more than two dozen vessels on patrol including cutters, RHIBs and jet skis. 

Gangs smuggling drugs by sea often rope in otherwise ordinary people to carry out their dirty work. 

This was shown in the recent case prosecuted at Truro Crown Court, which included a Hampshire fisherman who had been facing financial difficulties. 

He was joined by three Essex men who are believed to have been planning to sell the drugs in the south-east of England, and a Colombian who is alleged to have been acting as security for the drug cartel.  

Jurors heard that the conspirators had been due to collect 20 bales of cocaine from the sea after they had been dropped there by a cargo ship.

The prosecution said the drugs were brought from South America on a cargo vessel across the Atlantic and were dumped in water tight bales into the sea in the English Channel.

The bales were fitted with GPS tracking devices attached to Apple air tags so that they could be recovered from the sea by the smaller vessel and transported to mainland Cornwall. 

But despite the technology, the three men on the boat only managed to find eleven bales but dumped them during the chase.

They were Scott Johnston, 39, Peter Williams, 43, both from Hampshire, and 32-year-old Colombian Tabora Baca, 32. 

Baca - who claimed to be a tourist who had accepted a boat invitation from two strangers to go fishing - was the Spanish speaking link between the higher figures in the operation and had flown into the country on several occasions. 

The other conspirators were arrested at later times after National Crime Agency investigators trawled through CCTV footage, phone call data and phone messages.

Alex Fowlie, 35, of Chichester; Bobbie Pearce, 29, of Brentwood, Essex; Michael May, 47, also of Kelveden Hatch, Essex; and Terry Willis, 44, of Chelmsford, Essex, helped plan and organise the cocaine smuggling operation and pick up.

Gangs dumping drugs at sea after they realise police have been monitoring them is a common tactic to try and evade prosecution. 

In some cases, these packages have washed up on beaches, including in Cornwall and Sussex. 

Tom Chandler, a leading UK expert on drug cartels, told MailOnline that yachts or fishing boats transporting drugs can also get into trouble in stormy weather and sink, leading to drugs being washed ashore months later. 

In September, a black holdall containing around 40kg of the Class A drug was found on the sand at Trevaunance Cove in St Agnes on the north coast of Cornwall. 

An image taken outside Schooners bar overlooking the cove showed a police officer talking to members of the public beside the bag, while a lifeguard monitors the beach.

Another haul, weighing 30kg and believed to be worth around £2million, washed up in 2023 on a beach in Goring, West Sussex. 

Separate incidents involved a fisherman finding hundreds of kilos of cocaine floating near two Dorset beauty spots, St Aldhelm's Point and Durdle Door, and litter pickers stumbling across discarded packages on the Isle of Wight.

Border Force takes sniffer dogs with them to sea to detect drugs on any intercepted vessels. 

In January, a springer spaniel called Flash sniffed out a £50million haul of cocaine on a ship that had been intercepted off the coast of Dover. 

The haul, which had been hidden among bananas, had been packaged up in sealed bags fitted with trackers - ready to be flung overboard and later recovered. 

Senior Border Force Director, Duncan Capps, said: 'Border Force officers remain one step ahead of the criminal gangs threatening our border security as we continue to make record breaking seizures to keep deadly drugs off our streets.

'Our message to these criminals is clear – more than ever before, we are using intelligence and international law enforcement co-operation to disrupt and dismantle smuggling operations.

'We will continue to work with law enforcement to ensure those caught smuggling will face the full force of the law.'