Why are the IRA attacking agian?

Why did the IRA phone in a bomb call into central bombing? Why are they starting it all agian? Is this nothing more than a Irishman who happens to own a phone, or is the Irish starting agian? Do you think it is quite cool how the IRA are? How they are smart and crafty? But they are also quite ruthless, like that attack on a Coach in England carrying British soldiers on leave, the bus also carried families of the soldiers who greeted them when they arrived back in Britain. Do you think the Irish will start bombing London agian? Or is it nothing more than an individual phoning in a bomb threat and the police have no choice but too take it serious incase it is another group, such as the Muslims carrying out a terrorist attack in the name of Osama.