Following on from the issues of metal detecting , where for many, their only interest in the hobby is for profit, more efforts need to be made to ensure that archaeological finds are reported properly in the UK, as evidenced by the colossal (bearing in mind the size / population of the country) figures for artefacts not being handed over in Northern Ireland.
Irish Central 
Public hold on to 1.5 million archaeological finds – fail to hand in finds to museums
Ancient finds stuck in limbo in Northern Ireland
Updated Tuesday, July 3, 2012, 9:56 AM
By ANTOINETTE KELLY, IrishCentral Staff Writer
Over one and a half million Northern Irish archaeological finds are still in possession of the private companies that unearthed them.
The ancient remains, including pottery, metalwork, and human remains, were discovered by commercial companies redeveloping construction sites for new roads or buildings.
Since 1999, an estimated 1.47 million objects which were uncovered in Northern Ireland have been held by commercial companies. A dispute over ownership of the objects and a lack of facilities means the items have remained in the private companies.
According to the Northern Irish assembly, the current legal framework does not allow for the passing of archaeological archives produced through the planning process to local museums, except through a subsequent loan from National Museums Northern Ireland.
The Portable Antiquities Scheme states all archaeological finds discovered in Northern Ireland are normally the property of the landowner.
There has been a legal obligation to report the discovery of all archaeological objects found in Northern Ireland since 1926.
One of the most substantial recent finds was in Loughbrickland in Co. Down where Neolithic and Bronze Age remains were found in 2005 during construction of a motorway.
They included evidence of three Neolithic houses dating back over 6,000 years and a Bronze Age burial site. The artefacts found include whole pottery bowls, polished stone axes, and flint arrowheads.