A "keen angler" who went missing on a trip to France 20 years ago has been declared dead after a judge found he actually drowned in the English Channel during a suspected botched drug smuggling operation.

Kent dad Anthony Dugdale, then 43, disappeared after travelling to Calais towing a speedboat on a French ferry with a friend in April 2004 and has never been heard from since.

His Mercedes was later found abandoned close to the coast on the Belgian side of the French border, but the boat was never discovered.

Although the missing persons case initially focused on claims the pair were angling pals, police later turned their attention to drugs after evidence emerged of involvement with dealers.

Now, after an application to the High Court by Mr Dugdale’s son Danny to have his dad declared dead, a judge has ruled that he in fact died at sea in April 2004.

The judge, Master Karen Shuman, said evidence from police inquiries suggested that Mr Dugdale - who was "not an able seaman" and had previously been rescued from the Channel on another attempt to cross - drowned after trying to cross in an unsuitable speedboat and being hit by a container ship.

Anthony Dugdale went missing in April 2004 (Police)

The court heard Mr Dugdale, from Orpington, Kent, had travelled to France with friend Richard Patwell, from Alloa, Scotland, taking along a speedboat he had bought for £11,000 cash shortly beforehand.

Passenger records showed they travelled on a SeaFrance ferry, but did not use their return tickets, with the car discovered close to the Belgium-France border later. A boat cover was found with the car, but there was no sign of the speedboat.

Despite extensive inquiries and public appeals focussed on looking for two "keen anglers," Mr Dugdale and Mr Patwell were never found.

The mystery was finally cleared up at the High Court this week after an application by Mr Dugdale’s US-based son for a declaration of death so that his dad’s £33,000 estate can be administered.

Representing the son, solicitor John Davies told the judge that police had investigated thoroughly and come to the conclusion that Mr Dugdale had gone to France to smuggle drugs across the Channel.

"The conclusion of the police was that Mr Dugdale travelled to France to import drugs into Britain at night in a boat that was unsuitable," he said.

"There are strong and reliable implications that both were involved in dealing and importation of illegal drugs by boat across the Channel."

When buying the speedboat, he had given the seller the impression that he had no idea about boating and no idea how to look after an engine, said the lawyer.

The boat itself was unsuitable for crossing a busy sea lane and would usually only be used within two miles of shore, while Mr Dugdale also had a petrol canister on top of the back supports, making the vessel unstable.

He and Mr Patwell had also turned off their phones before they reached Dover, making it impossible for them to be tracked by mobile mast evidence, he said.

There was also some evidence of a distress call having been made from the Channel, describing engine troubles and having just avoided being hit by a ship.

Overnight on the day they left the UK, holdalls containing cannabis had also been found by French authorities floating in the Channel, he continued.

"It would seem quite coincidental if this was not on board," the solicitor said.

"The police concluded that it was most likely that he was hit by a container ship and sunk in the English Channel."

Mr Davies said there was further evidence linking Mr Dugdale to crime, having worked on a Welsh farm which was later found by police to be a working cannabis production facility.

He had also been picked up in the Channel months earlier, without a passport and suffering from hypothermia, with another man who was later convicted of involvement in the Welsh cannabis farm.

Giving judgment and declaring Mr Dugdale dead, the judge said: "The police have said that a full investigation has been carried out and they have closed the file.

"Their conclusion is that Anthony and Richard were on a drugs run from France. They had bought a high-powered speedboat and trailer for cash.

"They turned their phones off before Dover. The car was discovered in Belgium by the coast.

"The police have concluded that what actually happened was Anthony and Richard were trying to cross the Channel at night with a speed boat.

"They were most likely hit by a container ship and sunk. The speedboat they were using was one not suitable for crossing a very busy Channel.

"I am satisfied on the basis of the evidence before me that Anthony did indeed die in the Channel at some stage between April 7 and April 9, 2004."

The ruling means that, more than 20 years after he was last seen, Mr Dugdale’s £33,000 estate can finally be properly administered.

He had one son, Danny, and may have had a daughter, the court heard.

The whereabouts of his companion, Mr Patwell, was not part of the High Court case and so no findings were made in relation to him.