Yep, Cell Phones have been a major part of EW operations certainly since 1991 and certainly a major part of UK military and police operations since that time.

One of the first things the Ukrainian Security Forces went out a brought in 1991-3 was cell phone tracking and intercept technology, along with almost anybody else who could afford it.

Even back in the old days, i remember being told, that the technological blocks intercepting and tracking almost anyone using any computer network, land line or cell phone were negligible and the greatest challenge was human and organisational, even with voice recognition software!