My own personal version of Rampart Social Centre would be that it was born, together with many other squats in 2004, out of the need to house hundreds of attendants to he European Social Forum and adjacent alternatives.
The meetings for the preparation of said forum did acknowledge the need, and the problem of accommodating such a big number of people in the most expensive city in the UK, probably Europe.
But the possibility of housing them in squats was mercilessly laughed at in the ESF meetings.