Archaeologists are claiming to have discovered the oldest house in Britain.
The circular structure, found at a site near Scarborough, North Yorkshire, has been dated as being made in 8,500BC.
Described as a "sensational discovery" by archaeologists, this is 500 years earlier than the previous oldest house.
The teams from the universities of Manchester and York are also examining a nearby wooden platform, which is being claimed as the oldest example of carpentry in Europe.
Nicky Milner, an archaeologist from the University York, says such sites are "incredibly rare" - and that finding such early evidence of settled living gives a new insight into hunter gatherers.
"What's really important is how it changes our view of hunter gatherers," says Dr Milner.
"There was a view of them as being very nomadic, highly-mobile people - but now we're seeing them as much more settled and sophisticated... People were living in the same places for generations."
"This is a sensational discovery and tells us so much about the people who lived at this time," says Dr Milner.
Evidence of what would have been a 3.5 metre diameter house has been found at the Star Carr archaeological site, which was occupied by hunter gatherers 11,000 years ago, when Britain was attached to continental Europe.
The remains were dated by radio carbon and the type of tools used - which have identified the house as being from 8,500BC, older than the previous oldest known house, in Howick, Northumberland.
The people living here would have been among the first settlers returning after the glaciers of the ice age had retreated.
It was a round house - a smaller version of iron age round houses - with a circle of timber posts around a sunken circular floor area, which could have been covered by reeds.
It is not known how the walls and roof were covered, but it could have been thatched or used animal hides.
Archaeologists believe that the house had been rebuilt over time and that there were likely to have been other houses at the site.
It suggests that people of this era were more attached to settlements than had been previously thought - staying in one place rather than drifting across the landscape.
The Star Carr site, inhabited after the last ice age, is believed to have been in use for between 200 and 500 years.
It has been the subject of extensive research and excavation since its discovery in the 1940s - and has yielded items such as the paddle of a boat, arrow tips and masks made from red deer skulls.
There are also antler head-dresses, which could have been used in rituals.
The people living at Star Carr were hunters rather than farmers, catching animals such as deer, boar and elk, helped by domesticated dogs.
Archaeologists are also examining a wooden platform made from split timbers, near to the lakeside house, which is being claimed as the oldest example of carpentry so far discovered in Europe.
An 11,000-year-old tree trunk has also been found at the mesolithic-era site, with the bark still intact.
Chantal Conneller from the University of Manchester said: "This changes our ideas of the lives of the first settlers to move back into Britain after the end of the last ice age.
"We used to think they moved around a lot and left little evidence. Now we know they built large structures and were very attached to particular places in the landscape."
The teams were congratulated by Universities Minister David Willetts: "This exciting discovery marries world-class research with the lives of our ancestors.
"It brings out the similarities and differences between modern life and the ancient past in a fascinating way, and will change our perceptions for ever."