London - Black referees are failing to get into the upper reaches of English football because of the way they are assessed, a campaigner said Tuesday.
Reuben Simon, an ambassador for black, Asian and minority ethnic (BAME) officials at Ref Support UK, said overt racism at worst and unconscious bias at best were both playing a part in blocking the progress of non-white referees.
Uriah Rennie was the last black referee in the higher reaches of the English game before retiring in 2009.
There are no BAME referees currently working in the top four divisions, and only one in the National League.
Match assessors at all levels of English football examine the performance of referees, with their findings playing a key role in how far up the league ladder officials climb.
But Simon said a new system of assessing the assessors was needed to combat discrimination.
"It's a myth that there's a lack of black referees -- there are loads at grassroots level but they are not progressing up the pyramid," Simon told Britain's Press Association.
"Why? They are being blocked. There is a ceiling for black referees and it is non-league.
"When a footballer is very good it's obvious and it's in the manager's interest to pick them. So even managers with racist views have picked black footballers.
"But decisions about referees are more subjective."
Simon said while there was "nothing wrong" with observers mainly being "white chaps of a particular age" even well-meaning officials could discriminate against black referees.
"Most try to be as fair as possible. But there is also no question there is a lot of unconscious bias in the ratings," he added.
Simon said the Football Association, English football's governing body, could start to rectify the problem.
"Let's pretend that every black ref is rubbish -- it's possible, not probable -- but let's check that by sending out a ghost observer to the same games as those assessors who give black refs poor marks. And let's do it a few times, just to make sure," he said.
Simon's comments will add to the debate about racism in football, with black players such as England's Danny Rose and Raheem Sterling both lamenting what they see as a lack of significant action by football chiefs in tackling the issue.