A pair of giant bronze lions in the style of those which famously guard Trafalgar Square could sell for up to £100,000 at auction.

The statues, modelled on the originals designed by artist Sir Edwin Landseer which surround Nelson's Column, are due to go under the hammer in Billingshurst, West Sussex, on Tuesday.

At nearly four metres in length and just under two metres tall, they are almost identical in size to their counterparts but were made in the late 20th century for Camden Lock market. Landseer made his name by creating the four bronze lions on commission for the government in 1858.

They will appear at Summers Place Auctions alongside the first complete family of prehistoric mammoth skeletons ever to go under the hammer.

The collection of four Ice Age forms includes a one-year-old infant, only the second known complete baby mammoth skeleton in the world.

The infant, which is 155cm tall and 284cm in length, is joined by a slightly bigger young female, aged around eight or nine. Her skeleton is 195cm tall and 325cm. They are accompanied by an adult male which is 240cm tall and 400cm in length and an adult female which is 200cm tall and 328cm in length.

The highly anticipated lot failed to sell when it went under the hammer for the first time in November for a minimum of £250,000. But the skeletons did attract bids up to £240,000.

It is unknown exactly how the family died but their remnants were found together during building works near Tomsk, Siberia, in 2002.

Their relatively small frames indicate they lived in poor conditions and most probably died at the end of the Pleistocene period, around 12,000 to 16,000 years ago.

The auction house is keen for the skeletons to remain as a group because of their historical importance and had hoped a museum would snap up the chance to be the first in the world to show a family scene of the ancient, extinct species.

Summers Place director Rupert van der Werff said: "For comparatively a small amount of money (given their significance) it seems a great shame they may get split up. The mother and baby will be sold together as it would be awful to break them up."

A rare SA-4 Ganef rocket will also be on offer on the second day of the "conversation pieces" auction on Wednesday and is expected to sell for up to £25,000.

The Soviet-made medium-range air defence missile measures just under nine metres in length and three metres wide. It was first unveiled during a military parade in Moscow in May 1965 and reached speeds of up to Mach 4 with a range of between 31 and 34 miles.