"Celebrity Big Brother" over in the UK dressed contestants as border patrol agents and had them build a wall ... then they tried to stop intruders from getting their hands on a green card.

Trump even made an appearance ... sort of.

Someone on the production team dressed up as Trump ... then hopped over the wall and snagged a green card before the housemates shut him down.

The makeshift border wall split the house in two ... and everyone seemed to have their fun at Trump's expense.

The wall featured a striking image of the American flag ... and at least one contestant was NOT DOWN with the segment.

Trump wasn't the only political figure to be lampooned ... there were also impostors of Melania Trump and Queen Elizabeth. Trump is hated by many in England for a variety of reasons.