BT engineers uncovered a WWII-era mortar during trenching works at West Pinchbeck near Spalding. After the Police were informed, an Explosive Ordnance Disposal (EOD) team was mobilised. They confirmed the device as inert and removed it for disposal.
Used throughout WWII by British and Commonwealth forces in both training and combat roles, mortars remain one of the most common UXO finds in the UK.
See: https://lincolnshirereporter.co.uk/2018/09/engineers-discover-unexploded-bomb-in-lincolnshire/