“Modern watches and jewellery are out and so even is modern underwear as the danger is apparently too great it could be seen if we bend over,” an on-set snitch told the UK’s Telegraph.
“They have relented in the case of prescription glasses and asthma guns, but that’s about it.”
The strict rules come after a press photo fail made headlines last week.
Related: See the hilarious Downton Abbey press photo fail
The image depicted Robert Crawley, played by Hugh Bonneville, and Lady Edith, played by Laura Carmichael, dressed in authentic regalia but a modern day mineral water bottle was left on the mantel piece in the background of the portrait.
Would you like to know more? Head to: http://t.co/h7CwHKrHQg #Downton #wH2oops pic.twitter.com/kYieMmBVkf
While it was supposedly an innocent mistake, the show’s creator, Lord Fellowes, who values the show’s historical credibility, was said to be upset with the blunder.
Taking it all in their stride, the cast of the show snapped a tongue-in-cheek shot to support the work of charity WaterAid, an international organisation which provides clean water and toilet facilities to underprivileged communities.