A member of the “Real IRA” (a splinter group of the Irish Republican Army) has been convicted to seeking to purchase thousands of pounds of bomb-making materials in Lithuania which he planned to use in attacks in London.

Michael Campbell, 39, was caught with the help of an MI5 informer after a six-year sting operation.

Following a two-year trial, He was sentenced to 12 years in prison in Lithuania for a raft charges, including support of armed violence, smuggling guns and explosives and possession of firearms.

According to investigators, Campbell paid 6,000 euros ($8320) in exchange for high-grade explosives, grenade launchers, detonators, AK-47s and a special assassin’s rifle, to Lithuanian agents who were posing as arms dealers from Chechnya.

In a taped audio recording, Campbell boasted of how easy it would to carry out a terrorist attack upon London.

An undercover agent for MI5, named Robert Jardine, was instrumental in the Campbell case, providing crucial intelligence on the activities of the terror groups plans.

Irmantas Mikelionis, Chief Prosecutor of Lithuania’s Organized Crime Department, told reporters: “Operations like these change human lives. Secret agents knew about the dangers they may face but they performed their duties and demonstrated their courage and commitment. The dangers of being disclosed, the danger of being accused for co-operation with secret services were hanging in the air each time they contacted the members of the terrorist group.”

He added: “If we failed to stop Mr. Campbell, we would put in danger the lives of innocent people.

In response to Campbell’s conviction and imprisonment, Britain’s Home Secretary Theresa May, said in a statement: “I’m pleased with this verdict which has brought a dangerous man seeking to obtain weapons and mount attacks in Northern Ireland and Great Britain to justice. We know we face a real and serious threat from terrorism. I would like to thank the Security Service and the Lithuanian authorities who have worked tirelessly and bravely together on this operation.”

Liam Campbell, Michael’s older brother, was a leader of Real IRA and has already been found liable in civil court for responsibility for a 1998 bombing in Omagh, Northern Ireland, which killed 29 people.

Real IRA, also known as Óglaigh na hÉireann (Volunteers of Ireland), was formed in 1997 in the wake of disagreements with the Provisional IRA. Real IRA seeks the total reunification of Ireland. Aside from the 1998 Omagh bombings, the group also took responsibility of a March 2009 attack on the Massereene Barracks in Northern Ireland, which killed two British soldiers.