My Worrcester Bosch 280combi boiler's pilot light has gone out an wont relight no heating an no hot water Why?

if you can get it to light hold down for 15 sec, and let go of the pilot on, if it goes out when you let off the on, it is the copper wire that you have to replace first, shut the gas off at the valve their, light the pilot get the gas out of the line, probaly a couple of hex screws that are a flat head or filips, the nut on the gas valve has to come off to like a 3/8 or 7/16, unit comes out probaly another hex screw holding on the "thermocoupler" on the pilot lite end, be a little tuffer to get off probally bit rusty, trip to local hard ware, menards low home depot, probaly all have them. Replace and turn on gas relite. might take a min or blow out your flame.