A potentially unstable chemical weapon could be buried beneath an airbase that will shortly become home to over 900 army personnel, it has emerged.
RAF Kinloss in Moray is currently the focus of an investigation into radioactive contamination, but a report emerged on Sunday suggesting that the site could also be contaminated with mustard gas.
Officially known as sulphur mustard, it is a colourless oily liquid which can cause severe burns and cancer when released into the atmosphere.
A land quality assessment uncovered on Sunday by BBC Scotland identified potential sulphur mustard contamination in 2004 before construction work began on a new pipeline for a water treatment project.
About 930 personnel from 39 Engineer Regiment (Air Support) are due to move from Waterbeach, Cambridge, to Kinloss in July where they will provide engineer support to both the Royal Air Force and the Army.
A Ministry of Defence spokesman said: "Our investigations to date suggest there is no indication of significant risk to public health or the environment associated with the past storage or disposal of chemical weapon agents in the UK.
"Work undertaken indicates the sites are suitable for their current use, provided that any management systems, restrictions or procedures remain in place."
Thomas Docherty MP, a member of the Commons Defence Select Committee, said he has called for an urgent statement by the UK Government.
He told the BBC's Sunday Politics Scotland: "The MoD has had a culture over seven decades of not sharing information. There's an arrogance about the MoD that is not new, but it has to be tackled once and for all."
He added: "We need an urgent statement from the UK Government that spells out exactly who knew what when, that says what is the actual independent scientific risk, when did they inform the Scottish regulators, when did they inform the local authorities, and when did they inform Scottish ministers? And that needs to be done as soon as practicable."