A cautionary tale, trotted out again
When BT got too close to Huawei it caused all sorts of problems with their accreditation status, in fact I believe it lost it for traffic over the PSTN. Even if it didn't many security focused government services refused to have BT as their carrier. I understand that BT has taken steps to rehabilitate themselves, but the damage still lingers.
With Symantec the problem would be the same, the governmental trust level would be broken, and Symantec technology is widely used.
Would you want to be the VP who had to report, we've done this bang-up deal to share technology and cut costs, but we've lost all our government business in the west. I always wonder what happened to the BT director who signed up Huawei.