From 6 April the qualification period for an employee to bring a claim for unfair dismissal will increase from one to two years for employees who start work for their employer on or after 6 April 2012.  However, employees will still be able to claim within this period if they are able to claim for discrimination or for an ‘Automatic Unfair Dismissal’ where there is no requisite qualifying service needed, e.g. for whistleblowing or taking action on safety grounds.

See http://www.businesslink.gov.uk/bdotg/action/detail?itemId=1073793719&type=RESOURCES