Women who were once held at Yarl’s Wood were among those who turned out for a protest outside the controversial immigration centre.
Around 700 people are estimated to have been at Saturday’s rally, with people coached in from all over the country.
The demonstration, organised by Women for Refugee Women, called for an end to detention and for Yarl’s Wood in Clapham to be shut down.
Sophie Radice, from the charity, said: “For the women who returned it was scary to be back there and quite disturbing, but at the same time they really wanted to show that the women inside haven’t been forgotten.
“The most moving moment was walking around the fence and being at the back of Yarl’s Wood and seeing women inside waving their hands and calling out.
“I spoke to a lot of the women inside later by phone and they were really happy to hear us and see us.”
It was scary to be back there and quite disturbing.Sophie Radice, Women for Refugee Women
At one point during the protest, a fence at the rear of the site was dismantled in a show of strength of feeling.
Sophie said: “We didn’t encourage it but it was a very symbolic moment.”
The centre’s boundary is protected by a brick wall, which meant protestors did not have contact with those being kept inside.
No-one was arrested during the demonstration.