British prime minister Tony Blair is under renewed pressure to abandon his controversial "on-the-runs" legislation amid claims that it will discriminate against members of his own security forces.
The damaging claim, detailed in a legal opinion for opposition politicians, last night prompted Conservative Northern Ireland spokesman David Lidington to call on Mr Blair to "do everyone a favour and drop this Bill now".
At his press conference yesterday Mr Blair confirmed his intention to proceed with the Northern Ireland (Sentences) Bill despite the declared opposition of all the political parties in the North including Sinn Féin.
However Mr Lidington reflected a growing belief at Westminster that the prime minister will be forced to drop the bill, or at least radically amend it, in light of the legal opinion suggesting that OTR terror suspects are less likely to be found guilty by the proposed special tribunal than are members of the security forces or others charged with offences committed prior to the Belfast Agreement.
This opinion, which The Irish Times has seen, cuts across the SDLP/Sinn Féin debate about the apparent parity afforded by the bill to OTRs and security personnel accused of collusion.
More crucially, it threatens to destroy the argument which Northern secretary Peter Hain hoped would defuse Conservative and Unionist opposition.
The alleged discrimination against members of the security forces arises from the differing procedures proposed for dealing with the various categories of suspects covered by the legislation.
The opinion says the Bill "discriminates heavily in favour of OTRs in comparison with everyone else" because the OTRs alone would not be subject to arrest and interrogation.
"The crucial significance of this contrast is that whereas the court or 'Special Tribunal' can draw inferences adverse to the accused from silence or answers given in the course of interview or interrogation, this has no application to OTRs but does apply to members of the security forces," according to the legal opinion.
"Therefore, the machinery is highly discriminatory in that the possibility of conviction of OTRs is greatly reduced in comparison with members of the security forces who are prosecuted."
It continues: "This prohibition of the normal incidents of a full police investigation will also have the consequence that the trial of OTRs is likely to amount to little more than a sham. The Special Tribunal, administering the rules of the criminal adjudicative process, will be compelled to acquit many more of the OTRs than would otherwise be the case - a result even better than a pardon. Members of the security forces, on the other hand, remain just as liable to conviction and will bear the stigma of it subject only to the ameliorating effects of other provisions proposed in the Bill."
Mr Lidington maintained it was "odious" for the Bill to accept "the moral equivalence" of terrorists and the security forces. However, he said: "It's now clear the terrorists are getting a better deal."
An OTR is entitled to a certificate of eligibility to have his case processed under the scheme if he applies and certain conditions are met. Once he obtains his certificate he cannot be arrested or detained, nor can any search be made of his property or belongings, nor may fingerprints or samples be taken in relation to any offence covered by his certificate.
Furthermore, "no power to obtain information in relation to criminal proceedings is exercisable in connection with" any such offence.
By contrast, a member of the security forces would only receive his certificate once charged.
Up until that point he remains subject to arrest and detention, the police power of entry and search can be exercised in relation to him, and he can be required to provide fingerprints and samples in accordance with the normal procedures which take place before a suspect is charged with an offence.