A "family" of four mammoths discovered buried together in Siberia will be sold at auction in Britain later this year.

The group consists of an adult male and female, plus two young mammoths aged nine and one.

The fossils were discovered together during building work in the city of Tomsk, Western Siberia, and are a long as a London bus laid end-to-end.

Summers Place Auctions in Billingshurst claims it is the first time a "family" like this has been sold together. The lot is expected to reach an asking price of between £250,000 and £400,000.

The auction will take place on 21 November at the West Sussex auction house which specialises in Natural History and outdoor statue sales.

Director Rupert van der Werff told IBTimes: "We have never heard of a group of full skeletons like this coming up for auction. This is very rare indeed."

The fossils were uncovered by construction workers in Tomsk who noticed a collection of bones near to where they had started to build.

Excavations revealed a group of four mammoths close to the surface. It then took experts around two years to assemble the four skeletons.

They were toured in exhibitions throughout Germany, France and Switzerland between 2004 and 2007. The group are transported in 16 boxes when they travel.

The animals died around 4,000 years ago. Van der Werff added: "They were found near where water had once flowed. So perhaps they were victims of a flash flood, or maybe a riverbank had given way. It would have had to be something pretty significant to take out adults as well as younger animals. But the likelihood is that we will never really know what killed them for sure."

The auction house expects sales from rich private collectors as well as museums for the lot, which will be sold as a group, by an anonymous seller.

"This is an extraordinary collection, so it would be nice if they went to a museum where the public could continue to see them," said van der Werff.