Sir Hugh Orde, the Police Service of Northern Ireland's chief constable, warned yesterday that groups such as the Real IRA would target England if they could. His warning came within hours of a PSNI statement confirming that its officers had set up a number of vehicle checkpoints on routes from the republic into Northern Ireland.

Vehicles were stopped and searched yesterday along a number of main routes, including the main Dublin to Belfast road at Loughbrickland.

Speaking at Stormont yesterday, Orde said groups such as the Real IRA intended to cause "much damage" to the peace process.

Although the chief constable said that at present he believed the Real IRA and other dissident factions did not have the capability to strike in England, they intended to do so. "They want to destroy what has been achieved in Northern Ireland," he said.

The Real IRA, which was blamed for the 1998 Omagh bomb massacre, has been re-organising over the last 12 months. Late last year it shot and wounded two PSNI officers in Dungannon and Derry.

The re-emergence is also causing concern in the republic, where Irish security officials say they have advised Bertie Ahern's government that a visit by the Queen this year could provide a rallying point for violent dissident republican protests.

Sources said they were particularly concerned about a rerun of the "Love Ulster" riots two years ago, when demonstrations against a loyalist march through Dublin ended with rioting and looting in the city centre.

Three years ago the Irish president, Mary McAleese, issued the Queen with an open invitation to the republic. However, it is understood the cabinet, including Ahern, have now decided that there will be no British royal visit in 2008.

The Queen will be in Northern Ireland just 24 hours before the 10th anniversary of the Good Friday peace agreement. Buckingham Palace has confirmed that she will attend a Maundy Thursday service at St Patrick's Church of Ireland Cathedral in Armagh city.