(Reuters) - British postal company Royal Mail on Wednesday won a high court injunction to stop strikes by its biggest union around the time of a national election on Dec. 12 and in the busy run-up to Christmas. Members of the Communication Workers Union (CWU) had earlier voted to go on strike, saying that the company had failed to adhere to a pension deal agreed last year, but the court ruled that that ballot was unlawful.The CWU called the judgement an "utter outrage".It had not given exact..