Start the official grievance process against the offender, take it to the top!
I get threats against my albion mugs, deliberately being dropped etc
In the past 2 years I've added 6 albion mugs to the common pool, trying to saturate the stock. Soon it will be unavoidable although the majority of colleagues are Liverpool!? (in sussex) and I refuse to handle those mugs.
Kill him, slowly. cut the body into small pieces and proceed to the Palace pier, throw bits of body in air and smile as the Seagulls devour his remains.