MR Tony Blair this morning warns the IRA that its campaign of terror and threat in Britain will make Sinn Fein's entry into the political process "all the more difficult".
Writing in The Irish Times, the Labour leader says the IRA must prove a commitment to exclusively peaceful methods before Sinn Fein can be asked to sign the Mitchell principles of democracy and non violence and take its place in multi party talks. A Labour government, he declares, "will be firm and resolute in the face of violence".
Mr Blair issues his warning as Mr John Major prepares to put the defence of the Union and the constitution at the forefront of the election debate.
Mr Blair couples his uncompromising message to republicans with a strong warning to loyalists against a repeat confrontation at Drumcree. Repeating Dr Mo Mowlam's pledge to implement the recommendations of the North Report on parades, Mr Blair says: "Labour is determined - this and every year - that the rule of law will be upheld."
Meanwhile, as opinion polls predict a historic Labour victory in Thursday's general election, The Irish Times has been told that Dr Mowlam is set to be appointed Northern Secretary in a Blair government.
Dr Mowlam was treated from January until mid March for a non malignant brain tumour and is now fully recovered. However, she has acknowledged to Mr Blair that her illness could prompt some people to question her fitness for the demanding Stormont post. It is understood Mr Blair told her it was not an issue.
And his article this morning carries a clear indication that she is his Northern Secretary in waiting. Promising that Labour would take positive steps to build trust and improve confidence between the communities in the North, Mr Blair says: "Mo Mowlam has made clear proposals in this area like guaranteed basic rights through the incorporation of the European Convention on Human Rights; new steps to combat discrimination at work; and improving community identification with policing."
Britons will go to the polls on Thursday amid unprecedented security to counter the heightened threat of IRA disruption. But Mr Blair insists: "The IRA's attempts to disrupt the election campaign will not succeed. The British people will not be moved by terrorism."
Asserting the democratic imperative that "even the smallest party" pursues its aims through exclusively peaceful methods, Mr Blair says this "is a lesson Sinn Fein must learn before they will earn the right to sit and talk with other democratic parties in Northern Ireland".
He continues: "There must be a genuine ceasefire from the IRA. It must he proven to be genuine in both word and deed. The appalling campaign of terrorism and threats that we are now witnessing in Britain will make their task of convincing people that it is genuine all the more difficult. If they do, then - and only then - could Sinn Fein be asked to sign up to Senator Mitchell's principles of democracy and nonviolence and take their place at the talks table."