This is from a brochure by the City around the time the estate was completed.

The Barbican Y … I’m sorry,  I mean Blake Tower. (We long-standing residents will always know it as the Barbican YMCA.)  But as I was saying, Blake Tower contains 74 flats created in 2015-6 by Redrow Homes.

But for decades as the local YMCA its rooms were home to students and visitors, and it contained 218 bedrooms. Like the rest of the Barbican Estate, the site and is owned by the City of London. The City built the Barbican YMCA building at 2 Fann Street between 1965-71 when they constructed the Barbican Estate, and they leased it rent-free to the YMCA. The YMCA building was part of Phase IV of the City’s building programme for the Barbican site. The contractor was Myton Limited, a subsidiary of Taylor Woodrow.

The building was designed by Chamberlin, Powell & Bon, who designed both the Barbican Estate and the earlier Golden Lane Estate on the other side of Fann Street. The YMCA Building was (so it is said) designed to unite architecturally the Barbican Estate with the Golden Lane Estate, which features a tower of the same height (Great Arthur House).

The building is concrete-framed and the surface of the concrete was pick and bush hammered (a distinctive feature of the Barbican Estate). The windows are made of steel and painted black. Room windows are slightly inset with central pivots. The north side and stairs have a continuous glazing band which is also set back slightly.

The ground floor of the Barbican YMCA building contained the reception area and a communal lounge. Floors 1-2 were used as a gymnasium and dance studios with associated changing facilities. The lower ground level contained a large canteen and kitchen areas. Below that the basement provided storage and meeting rooms.

Floors 3-10 contained bedrooms for men. Floor 11 contained staff bedrooms. Floors 12-15 contained bedrooms for women. Floor 16 was a penthouse flat for the warden. In the quaint City of the 1970s, eight floors of rooms for men were separated from four floors of rooms for girls by a single floor of staff flats – no doubt with a thin blue line of ex-prison warders manning the stairwells late at night.

When the lease came to an end the YMCA found other premises more suitable for their modern needs.