Politicians, lawyers and doctors express concern over use of expert witnesses in English courts

Questions raised about potential miscarriages of justice after use of such experts criticised in Lucy Letby and Post Office Horizon cases

• Who are expert witnesses and how does system work?

A lack of regulation over the use of expert witnesses in English courts could be leading to miscarriages of justice, senior politicians, lawyers and doctors have said.

The former attorney general Dominic Grieve and the former justice secretary Jack Straw were among those to tell the Guardian that criminal and civil trials were sometimes hanging on evidence by self-appointed experts" who could lack relevant knowledge.