SCOTLAND’S leading animal welfare charity used controversial methods to kill a harmless snake after mistaking it for one of the most dangerous reptiles in the world.

The Scottish SPCA is facing calls for an investigation after a timid tree snake was wrongly identified as a deadly green mamba and placed inside a freezer – against the charity’s own guidelines on good practice.

The creature was discovered last month on the UAL Bodewes cargo ship that had docked in Aberdeen after travelling from West Africa.

The Scottish SPCA was called out to rescue the reptile which was then taken to a rehoming centre under police escort.

Scottish SPCA chief superintendent Mike Flynn said: “The safety of our staff and the public is paramount and as such the snake was placed in a freezer where it passed away. Recent guidance issued on euthanising animals suggests that placing a reptile in a freezer is not the preferred method. However, in this instance freezing was considered the only safe option as any other method would have posed a significant risk to our staff.”