Johannesburg - Trade union Solidarity is contemplating a major legal onslaught against prison authorities over affirmative action, the union said on Wednesday."Over 30 individual cases could be consolidated, making this the biggest affirmative action case yet in South Africa," Solidarity deputy general secretary Dirk Hermann said."In these cases, the (correctional service) employees were the best candidates, but they were passed over for promotion because of the policy of absolute national demographic representivity."He said in a statement the correctional services department's affirmative action plan aimed to reflect the national demographics in every workplace, including provincial and regional levels.Hermann said there was an "outcry" last year after government spokesperson Jimmy Manyi said there were too many coloured South Africans in the Western Cape, and that they should be redistributed countrywide.Manyi also advocated absolute national demographic representivity in terms of employment."The... policy is the practical outworking of Jimmy Manyi's comments. (Minister in the Presidency) Trevor Manuel responded to Manyi in an open letter, stating that his comments were not in line with the letter and spirit of the constitution," Hermann said."In view of Manuel's strong stance against this form of affirmative action and his commitment to oppose Manyi's ideas, we invite him to add his voice to ours and fight with us to stop this affirmative action method."The correctional services department could not immediately be reached for comment.