Former Post Office IT chief claims Horizon system has no fundamental flaw

An original Horizon terminal, as supplied to post office operators, from the collection at London's Postal Museum. Photograph: David Levene/The Guardian

The former head of IT at the Post Office named by the ex-chief executive Paula Vennells as one of five people responsible for the Horizon scandal has said he still has not seen evidence of a “fundamental flaw” in the IT system.

Mike Young, who worked at the Post Office from 2008 to 2012 when the legacy Horizon was moved to an online system, was giving evidence to the public inquiry into the scandal on Tuesday, months after it was told “he could not be found” to add him to the witness list.