Retired dealer Alfred Fleming fears it now may be in Ireland or mainland Europe but hopes there is a chance it can be recovered.
The 6ft high teak statue of a warrior is one of a pair, representing mythical figures Gog and Magog, that were on plinths either side of the front door of the well-known Clock Tower building in Southsea.
Fleming and his family operated an antiques dealership from the building for 70 years.
He sold the shop to current occupier Tony Wood in 2005 and moved to the basement, where he traded until 2015 when he retired.
Wood runs his hairdressing salon from the Edwardian building and when he took over the property he renovated the premises and had the figures restored to their original teak finish. The figures were moved inside the shop but, as the building is listed, planning experts said the figures should be returned to the entrance.
They were secured within iron grills and CCTV fitted but at 2am on June 10 one of the sculptures was stolen.
The Clock Tower building on Castle Road was constructed in 1903/4 and it is believed the figures were carved by local ship figurehead craftsmen working at nearby dockyards.
The Fleming antiques business can be traced back to 1908 when Alfred’s grandfather operated from a number of locations including London and Southsea. In 1942 the family’s premises opposite The Clock Tower were bombed and the business moved to The Clock Tower.
Alfred’s uncle Jack, who had run the business since the Second World War, retired in 1994 and Alfred continued the firm with his wife Christel until 2015. He said: “Although I sold the building in 2005 I am still very attached to it and I really hope we can recover the missing figure.”
Anyone with information should contact Hampshire Police quoting crime reference number 44220231000, contact Crimestoppers anonymously on 0800 555 111, or contact firstname.lastname@example.org.