By Jeremy Grange
Producer, Hunting the Beagle
Dr Robert Prescott intends to end the 140-year-long mystery
A muddy river bank in the flat, watery landscape of southern Essex may seem an unlikely place to find one of the most important ships in scientific history.
But a combination of painstaking detective work and archaeology have convinced maritime historian Dr Robert Prescott that the banks of the River Roach near the village of Paglesham are the last resting place of HMS Beagle.
The historic ship will be forever associated with Charles Darwin who served as its naturalist on her second great voyage between 1831 and 1836.
This journey sowed in Darwin's mind the seed of the ideas that would eventually become his theory of natural selection and revolutionise the way we look at the world and ourselves.
Dr Prescott, from the University of St Andrews, decided to find out what happened to the Beagle after she completed her third and final great voyage in 1843.
"The notion that there was this interesting ship which also had a very interesting connection with one of the major scientific developments in recent history was just too good to be true. I wanted to find out more," he told the BBC Radio 4 programme Hunting the Beagle.
His first port of call was the Public Records Office in Kew where old naval documents are stored.
In the Admiralty Progress Book for 1845, he came across a few lines of handwriting revealing that after refurbishment at Woolwich Dockyard, the Beagle was transferred to the Coastguard at Paglesham for duty as an anti-smuggling watch vessel.
The maze of creeks and inlets between the River Roach and the River Crouch was a smuggler's paradise in the mid-19th Century and a carefully positioned watch vessel was a valuable weapon.
A document records the ship was decommissioned as a coastguard watch vessel, and sold off in 1870 to "Messrs Murray and Trainer".
HMS Beagle: It seems Darwin did not have "sea legs"
Dr Prescott believes this was probably an ad-hoc partnership of two local farmers who did not have any experience of ship-breaking and who would have salvaged what they could in difficult conditions.
"It would have been slippery, dangerous to work in and very difficult to dismantle," he explained.
"That's why I believe that the lower half of this vessel was probably abandoned and has slowly settled deeper and deeper into the mud," he added.
Dr Prescott and a team of archaeologists discovered a structure buried which matches the size and shape of the Beagle, after using ground radar and other geophysical techniques at the Paglesham site.
He hopes that by the end of this year the ship will once again be brought to light after 140 years buried in the Essex mud.
Cores taken at the site have been examined for diatoms
But to find out if the timbers are indeed those of the Beagle, the ship's bilges are being tested for remains of tiny marine organisms called diatoms.
Certain species of diatom are specific to particular parts of the world and if the team could recover diatoms unique to the Pacific or Australian waters then the buried hulk had to be the Beagle.
The first set of cores taken at the site are being analysed using a scanning electron microscope by David Patterson, professor of marine ecology at the University of St Andrews.
The results so far have been very positive: the cores have brought to the surface diatoms and what appears to be Beagle's timber.
"It's very like a forensic investigation," Professor Patterson said. "If we can get one particularly well-recognised diatom species that we know to be tropical, that would be the 'killer's fingerprint'."
While the team at St Andrews has been searching for the killer fingerprint, Dr Prescott has been discovering what the most famous member of the Beagle's crew thought of the vessel that was his home for five long years.
Darwin's ideas have had a profound influence on scientific thinking
In later life, Charles Darwin acknowledged the importance of the ship in his life's work despite being plagued by seasickness during the voyage itself.
Professor Keith Thomson, author of HMS Beagle - The Story of Darwin's Ship, said: "When they were at sea, Darwin mostly lay in his hammock, seasick.
"I haven't been able to find a record of anyone else who, on a voyage of five years, was seasick from the very first day to the very last," he added.
But the fact Darwin suffered so badly throughout the voyage only makes his scientific achievements during that time all the more impressive.