The conclusions of a British inquest into the 2004 sinking of a French trawler, which killed five people, will be delivered on November 5, the coroner said on Thursday.

Judge Nigel Lickley has been hearing evidence since early October about how the Bugaled Breizh sank suddenly off Cornwall, southwest England, despite good weather.

Five crew died on the Bugaled Breizh when it sank off the coast of Cornwall, southwest England, on January 15, 2004 Five crew died on the Bugaled Breizh when it sank off the coast of Cornwall, southwest England, on January 15, 2004 Photo: AFP / Fred TANNEAU

The bodies of two of the fishermen who died were recovered by British search and rescue teams.

Lawyers for the victims' families maintain that a submarine on exercises in the area at the time could have struck the boat and pulled it down.

But Britain's Ministry of Defence said none of its subs were active in the exact area and that the trawler's nets likely got caught in sediment, dragging it to the bottom.

The bodies of two crew members were recovered off Cornwall and a third was found during salvage operations, while the other two were lost at sea The bodies of two crew members were recovered off Cornwall and a third was found during salvage operations, while the other two were lost at sea Photo: AFP / FRED TANNEAU

Lickley, a high court judge sitting as coroner, was originally due to give his ruling on Friday but said he would delay to November 5 as he considers the evidence.

The London court has been told that three subs -- the Dutch Dolfijn, a German U22 and the British Torbay -- were operating in the general area close to the crash site, getting ready for planned allied military exercises.

But the families' suspicions were focused on another submarine, the Royal Navy nuclear-powered vessel HMS Turbulent.

The coroner's inquest at the High Court in London will hear evidence from submarine commanders in the area at the time The coroner's inquest at the High Court in London will hear evidence from submarine commanders in the area at the time Photo: AFP / DANIEL LEAL-OLIVAS

The navy, though, has ruled out any involvement, stressing that the Turbulent was docked on the day of the sinking, January 15, 2004.

Oliver Hyams, a lawyer for the families, has requested that the inquiry hear evidence from retired French admiral Dominique Salles, who has previously said that it was "possible" an allied submarine could have been involved.

MoD lawyer Edward Pleeth on Thursday denied the claims as both sides presented their final submissions.

Experts called during the hearing had "entirely ruled out submarine involvement", he said, adding that the evidence pointed towards a fishing accident.

"Every proposition of alternative explanations was rejected in totality by your independent counsel," he told the judge.

The French justice system, after years of investigations that delayed the full British hearing, said in 2016 it was unable to reach a definitive conclusion.

Coroners inquests are held in England and Wales to try to establish the causes and circumstances of sudden or unexplained deaths on the balance of probability.

They do not determine criminal or civil liability but set out facts in the public interest.

In particularly sensitive cases, including matters of national security, a judge can be appointed to oversee proceedings.