Union activist Pete Shaw has been injured following a confrontation with security outside the Merrion Centre in Leeds.
Pete Shaw, a Unite member was taking part in demonstrations against illegal blacklisting in the construction industry when the incident occurred.
According to unconfirmed reports, Mr Shaw has had an ECG scan and is suffering chest pains from being thrown to the ground.
Construction union UCATT have strongly criticised the heavy handed approach by security teams.
Rob Morris, Regional Secretary of UCATT Yorkshire, said:
“This was an appalling incident and was totally unnecessary. This was an entirely peaceful and good natured protest and for security to act in this way is reprehensible.”
The protesters were demonstrating as part of the TUC Day of Action on blacklisting outside the Merrion Centre where leading blacklisting company Robert McAlpine has an office.
According to the union, protesters had obeyed all the instructions to protest outside the building.
However trouble occurred when some of the protesters were invited to access the building to visit the offices of the PCS union which is situated inside the centre.