The RUC Chief Constable, Sir Ronnie Flanagan, has warned of a serious security threat posed by dissident republican paramilitaries and said any reduction in the size of the force envisaged in the Patten report is inconceivable while the threat exists.
He said his force and the Garda had successfully thwarted attacks from Continuity IRA, the "Real IRA" and breakaway members of the INLA, but they "pose a serious and growing threat, largely but not exclusively, along the Border".
Sir Ronnie told PA News that he feared dissidents had an "imminent determination" to carry out a bombing attack on a military target along the Border.
He said he would feel it necessary to tender his resignation if there was a reduction in the size of the force in the face of this security threat.
The Patten report proposes the downsizing of the force from 13,500 to 7,500 and the abolition of the full-time reserve.
"If the inconceivable should happen, that government would attempt to reduce our ability to protect the public at large. I couldn't be part of such a move," he said.
The 32 County Sovereignty Movement, which denies it is the political wing of the "Real IRA", responsible for the August 1998 Omagh bomb atrocity, described Sir Ronnie's claims yesterday as "sensational".
Sir Ronnie said: "It would have been their intention before this point to have engaged in a number of attacks and I have no doubt the steps we have taken and steps taken by our colleagues in the Garda Siochana have thwarted their intentions so far.
"That gives no room for complacency whatsoever. We believe they have the intention and the determination to attack police or military colleagues along the Border, but other types of attacks cannot be ruled out."
In a statement yesterday, Mrs Bernadette McKevitt, the chairwoman of the 32 County Sovereignty Movement, said Sir Ronnie's comments amounted to a "cynical attempt" to safeguard the jobs of RUC officers. Meanwhile, anti-agreement unionists have pledged to step up their opposition to the Patten report with a poster campaign and a series of rallies across the North.
Members of the Democratic Unionist Party, the Northern Ireland Unionist Party, the United Unionist Assembly Party and a dissident Ulster Unionist, Mr Peter Weir, yesterday launched the logo for their campaign "Defend the RUC - They Defended Us".
The first rally will take place in Newtownards, Co Down, next Thursday. The leader of the DUP, the Rev Ian Paisley, warned that if the British government tried to force changes the unionist population would protest.