About 30,000 working women in Britain are sacked, made redundant or leave their jobs every year because they are pregnant, a survey by the Equal Opportunities Commission (EOC) has found.

The survey, published on Wednesday as part of an EOC campaign for the rights of pregnant women, showed widespread discrimination against them in the workplace.

Of those questioned, nearly half reported experiencing some form of discrimination because of their pregnancy and a fifth lost their jobs or missed out on pay raises or promotion.

In a statement, the EOC said research for its campaign had unearthed many forms of pregnancy discrimination.

“These range from denial of promotion, bonuses and training opportunities and changes in job descriptions to being left out of decisions and even verbal abuse,” it said.

Olympic gold medal winner Denise Lewis, who experienced problems with her coach when she announced she was pregnant, has offered the campaign her support.

She was quoted on the EOC Web site as saying: “I really believe that women should not suffer at work just for being pregnant. For me pregnancy was a short pit-stop and I always believed that I would return to my career.”