Keith Vaz, the chairman of the Commons Home Affairs Committee, has written to the HM Crown Prosecution Service Inspectorate's chief inspector, Michael Fuller, urging him to examine whether the Crown Prosecution Service's (CPS) procedures were "sufficiently robust".
Conservative MPs expressed concern at the way charges had been brought in a number of high profile cases, including Mr Evans and Coronation Street stars Bill Roache and Michael Le Vell, also both separately cleared.
Mr Vaz has asked Mr Fuller to look into whether the CPS had followed due process in deciding whether to bring prosecutions, whether there was sufficient evidence to bring charges, and whether the procedures in such cases needed to be amended.
"Politicians should not become involved in the operational decision-making of the CPS. It is vital, however, that the processes followed by the CPS are correct and robust," Mr Vaz said. At the weekend, Mr Evans suggested the CPS should pay his legal fees which are due to run into six figures.