A National Trust manor where Bridgerton was filmed is at the centre of a murder investigation after a fight between two builders lead to one dying.
The victim, 28, made it home after the 'old fashioned brawl' but was later found dead in his home.
A 29-year-old man was arrested on suspicion of murder before being released on bail pending the results of a postmortem.
The fight is understood to have broken out following an argument between the builders on the grounds of Belton House near Grantham in Lincolnshire.
Building company Thomas Bow City Asphalt has confirmed they employed both men as subcontractors on the site on the grounds of the country manor.
The force said the fight did not involve any members of staff and volunteers for the National Trust, nor any visitors to Belton House. Pictured: The front of Belton House
Lincolnshire Police said the victim was involved in an assault at Belton House in Lincolnshire on Thursday. Picture: A scene from Bridgerton shot in Belton House
A volunteer worker at a makeshift visitor's reception described Thursday's incident as 'very alarming' and said National Trust staff and visitors were 'obvious' to it until police turned up.
The woman, who preferred not to be named, told MailOnline today: 'What happened is very sad and you don't expect a fight to break out leading to the death of someone at a place like this.
'But it is nothing to do with the estate, the staff or visitors and most are unaware of the drama. It involved the contractors.
'It centred on two builders working on site. We later heard there was some kind of argument and a fisticuffs style fight which may have involved a head injury.
'It was an old fashioned brawl and is not believed to have involved any weapon or tool.
'The injured person left the site seemingly okay but died later. It is a worrying and very alarming episode but really nothing to do with the estate.'
The victim and suspect both work for Nottingham-based Thomas Bow City Asphalt construction group which has been busy building a new car park and visitor's reception over the past months.
Work on site has temporarily been stopped while the police investigation is ongoing.
A police car remained at the premises as forensic experts continued searching for clues in a cordoned off area adjacent to the smart new car park which is still being built.
Crowds of visitors - many with young children- flocking to the country house which was hosting a Christmas lights spectacle trail within the beautiful gardens - had no idea about the crime on the doorstep with the cop vehicle barely visible in the fog-shrouded grounds.
Estate general manager Ian Cooper said: 'There is an ongoing police investigation and little we can say because it happened off site to the house and gardens.
'There was a fight between two builders and the area has been cordoned off by police.'
The 28-year-old man returned home after the altercation on Thursday at Belton House but later became unwell and died
Mr Cooper said anyone working on the site had to wear high viz gear and hard helmets.
He said the 'unfortunate' incident had neither affected staff working at the estate nor visitors and happened in an area not open to the public.
He said the reputable construction company had been 'working on site for many months rebuilding a car park and building a new reception and admission kiosk.'
A Lincolnshire Police spokesperson said: 'We are investigating the circumstances of an assault reported to have taken place at Belton House, near Grantham, after the death of a man.
'Officers received a report than an altercation had taken place at the property yesterday.
'A 28-year-old man was reportedly involved in an altercation before returning home, where he later became unwell and sadly died.
The force added: 'We are keeping an open mind into the circumstances of his death and investigators are following a number of lines of enquiry, including an area in the grounds of Belton House where this is believed to have taken place.
'This is not in the public spaces, and it is believed the people involved knew each other.
'The incident did not involve any members of staff and volunteers for the National Trust, nor any visitors to Belton House.
'Officers and forensic investigators will remain on scene at the property for at least the next day while they conduct initial enquiries.'
The man arrested on suspicion of murder but has been released on bail pending a postmortem.
A man, 29, has been arrested on suspicion of murder after a 28-year-old man died following reports of an 'altercation' in the grounds of a National Trust country house. Pictured: The rear of Belton House
Police have appealed to members of the public for any information which could help its enquiries.
They added: 'We are carrying out enquiries at a number of locations in Lincolnshire and Nottinghamshire', including at the country estate.
A spokesperson for Thomas Bow City Asphalt, said: 'First and foremost, our thoughts are with the family and friends of the man who sadly lost his life yesterday.
'We can confirm that both men involved in the incident were sub-contractors working on a Thomas Bow project that is currently underway at Belton House in an area closed to the public.
'We are unable to comment further due to the active police investigation that is underway.'
Belton House is a listed grade 1 building and was designed by William Winde and built between 1685 and 1688 by William Stanton.
It is marketed by the National Trust as 'the perfect English country house' and boasts a spectacular Christmas lights display.
When Lord Brownlow died in 1978, his son Edward John Peregrine became the seventh baron.
In 1984 he gave Belton House, its garden and garden sculpture to the National Trust which then bought the park of 1317 acres.
Thomas Bow City Asphalt is described as one of the biggest building and civil engineering contractors in the East Midlands.
The family-run business, founded 150 years ago, boasts on its website: 'With many accreditations highlighting our dedication and excellence, we pride ourselves on delivering high quality results with budget and to program.
'A trusted name since 1867.'