Sky News understands that Whitehall officials have been "seriously concerned" that campaigners would use international criminal rules to try to detain the Pontiff while he is in the UK.
Richard Dawkins, Christopher Hitchens and human rights lawyer Geoffrey Robertson QC were among those campaigners reported to be looking at the options for bringing a private prosecution in relation to the Pope's alleged cover-up of sexual abuse in the Catholic Church.
Now Justice Secretary Ken Clarke has proposed changes to the rules on universal jurisdiction, a law that allows individuals to be prosecuted in the UK for serious offences such as war crimes, crimes against humanity and torture even if they were carried out abroad.
The plans would mean the Director of Public Prosecutions would need to give his consent to any arrest warrant issued under universal jurisdiction.
This would effectively mean taking that power out of the hands of the courts.
Ministers say the current rules are open to abuse because the evidence required to get a warrant is far below the threshold that would be needed to bring a prosecution.
This has meant the rules are often used by those who wish to make a political statement or to cause embarrassment.
The most recent attempt to obtain an arrest warrant for a foreign dignitary was ahead of the visit by former Israeli defence minister Tzipi Livni who cancelled her trip at the last minute to avoid embarrassment.
"Our commitment to our international obligations and to ensuring that there is no impunity for those accused of crimes of universal jurisdiction is unwavering," Mr Clarke said.
"It is important, however, that universal jurisdiction cases should be proceeded with in this country only on the basis of solid evidence that is likely to lead to a successful prosecution - otherwise there is a risk of damaging our ability to help in conflict resolution or to pursue a coherent foreign policy.
"The Government has concluded, after careful consideration, that it would be appropriate to require the consent of the Director of Public Prosecutions before an arrest warrant can be issued to a private prosecutor in respect of an offence of universal jurisdiction."
The state visit this September will be the first visit by a Pope to the UK since 1982.
SIC: SkyNews