Connolly Brothers (Blackley) Ltd was established in 1919, when the assets of Connolly Brothers Ltd were sold to Enfield Cables Limited.

Connollys was a member of the industry body the Cable Makers Association, and was best known for its Blackley Tape product.

As well as the main works in Blackley, Manchester, the company had a factory in Kirkby and offices in London, Birmingham, Glasgow and Aycliffe.

The company became a subsidiary of British Insulated Callenders Cables Ltd in 1959, although it continued to operate independently, manufacturing telephone cable. It was became known as BICC Connollys Ltd in 1975 when a restructure of British Insulated Callenders Cables Ltd resulted in the parent company being renamed BICC Ltd.

In 1999, BICC Ltd sold its cable manufacturing business, including BICC Connollys Ltd, to Corning, which was acquired in turn by Belden Cables in 2000. Belden Cables maintained its operations at the former Connollys (Blackley) Ltd works.