[holding answer 30 June 2009]: The Home Office has not issued such guidance. The Home Office is currently considering the recommendations of the House of Commons Home Affairs Committee on this and other issues in its recent report on the Policing of the G20 protests.
If an officer is found to have deliberately removed his or her identification to avoid being held accountable, they breach the standards expected of police officers and would be liable to be dealt with under the disciplinary arrangements as set out in the Police (Conduct) Regulations 2008.