Police were called to the University of London Union’s Malet Street offices on 16 July by security staff to attend a reported act of criminal damage.
Officers arrested at 24-year-old woman on suspicion of criminal damage after coloured chalk was scrawled on the university’s Foundation Stone at its Senate House in Bloomsbury.
A group of protesters attempted to stop the arrest, which required additional officers to attend the scene.
Footage circulated on YouTube also shows the woman, whose hands were handcuffed behind her back, refusing to step into a waiting police van while students remonstrated with officers.
The woman was arrested on suspicion of assault and taken to Holborn police station, a police spokeswoman said.
Protesters picketed the police station throughout the evening to call for the protester’s release.
A statement issued by ULU has condemned the intervention of police and university officials as a “disgrace”.
It explained the “3 Cosas Campaign” demonstration was held to highlight that outsourced cleaners receive different levels of holiday pay, sick pay and pension entitlement than staff employed directly by the university.
“If there are ‘crimes’ on campus, it is the fact that many of the people who clean our buildings and cater our events cannot properly take days off when they get sick, have inadequate time to visit their relatives, and work significant periods of their lives with no prospect of a decent pension,” the statement read.
“Chalk can be washed off – that is the whole point of chalk,” it said.
Universities are “supposed to be places in which the freedom to dissent is enshrined, and in which the community can collectively and critically exist”, it added.
“In this case, university managers and the police worked together to attack this,” the statement said.
Union officers called on the university to issue an apology and intervene with the authorities to prevent charges being brought.
A second protest will be held outside the Senate House in Bloomsbury on 17 July at 1pm.
The demonstration follows the decision by the University of London in May to abolish its student union, which represents 120,000 students, and take control of the Malet Street building itself.
A University of London spokesman said it was “not in the university’s power to direct police nor can it decide whether or not to press charges for a criminal act”.
“Although the instigator thankfully only used coloured chalk, the Foundation Stone that [was] defaced absorbed some of the chalk’s colour,” the spokesman added.
“A specialist cleaning firm was called to steam clean the stone but further work will be required to reinstate some of the lettering.”
The university is in talks with recognised trade unions over working conditions for cleaners, he added.