Originally Posted by
UKtravelbear
No it won't - as previously stated several times - affect the OPs colleague flights.
Every individual has their own ticket even if it is part of the same PNR as other peoples. The two passengers may be on the same PNR but that is not the same as being on the same ticket
There is no need for the OP to tell anyone.
With many airlines, to get a voucher for the nonrefundable ticket value to use towards other flights, you need to cancel ahead of time. Other airlines, the voucher will be credited to your account even if you're a no-show. Not sure which category BA falls into, but might want to make sure of this just in case so you don't lose your ticket value.