The British and Irish Lions have been left furious at the decision to have a South African as the Television Match Official for the first Test against the Springboks in Cape Town.
Marius Jonker was chosen after New Zealander Brendon Pickerill was unable to travel because of the Covid-19 pandemic.
Lions sources added they were only informed about the switch on Wednesday.
Kick-off at Cape Town Stadium is 17:00 BST on Saturday.
The tourists believe there should have been a contingency plan in place for an alternative, neutral official.
Jonker, who was the TMO for the recent match between the Lions and South Africa A, will be the TMO for the entire Lions series against the Springboks.
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Lions boss Warren Gatland is thought to be furious at the decision with Lions sources saying they were "astonished" to only be told of the switch at late notice.
World Rugby, who appointed the officials for the series, say flying in an alternative TMO was not possible because of various Covid-19 restrictions.
'Home' TMOs were used during last year's Rugby Championship.
Australian Nic Berry will referee the match in Cape Town, with the Kiwi Ben O'Keeffe and Frenchman Mathieu Raynal as his assistants.
Following the Lions' 17-13 defeat by the Springbok-laden A side, Gatland said scrum-half Faf de Klerk could have been sent off for making head contact with Josh Navidi, while South Africa director of rugby Rassie Erasmus later took to social media to highlight Owen Farrell's tackle technique.
The Lions series in New Zealand in 2017 swung on a red card for All Blacks centre Sonny Bill Williams, with the Lions making the most of the numerical advantage to come from behind to win the second Test in Wellington.
With officials continuing to crack down on foul play and head contact, a red card in the upcoming series between the Lions and the world champions is a distinct possibility.
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