Despite these and many other responses to the IRA's campaign in Britain since 1988, the bomb in Bishopsgate showed that terrorists can still strike with impunity and to horrendous effect in broad daylight in the heart of the City of London.
The bomb raises the question of whether more can be done to combat the terrorist campaign. MPs and terrorism experts were quick to re-open the debate about the effectiveness of the police and MI5.
David Mellor, a former Home Office minister, said: 'There is no doubt that the IRA have got more professional. The terrorists have raised their game, they are more daring and more contemptuous of public opinion and they are better organised . . . we must raise our game too. We are not striking back effectively.'
Speaking on BBC Radio, he pointed out that there had been no arrests for many of the major recent IRA atrocities: the 1990 murder of Ian Gow, the Tory MP for Eastbourne, the 1989 Deal bombing, or the Warrington explosion.
Mr Mellor said it was important to examine how the terrorists had managed to plant the Bishopsgate bomb, whether MI5's involvement in intelligence gathering was working and whether there was sufficient funding for the anti-terrorism effort. He also questioned whether the anti-terrorist branch contained police of the highest calibre.
Calls for a national anti-terrorism organisation were repeated yesterday by Paul Wilkinson, Professor of International Relations at St Andrew's University, Fife, and a leading expert on terrorism. The present arrangement was 'a recipe for fragmentation', he said. 'They are simply unable to keep pace with the IRA.'
Often, in Northern Ireland, intelligence is not shared between the Army, the security service and the Royal Ulster Constabulary, so that liaison with the agencies in Britain is inevitably difficult.
In Britain, Scotland Yard's Anti- Terrorist Branch handles investigation and evidence gathering. Although its last head, Commander George Churchill-Coleman, was appointed national anti-terrorism co-ordinator to give him more say over provincial investigations, the post has little power and the branch still has to defer to local sensibilities.
The high profile he was given, by his superiors, led to the inaccurate conclusion that he alone led the fight against terrorism. Similarly, when responsibilty for co-ordinating intelligence was moved from Special Branch to MI5, it was wrongly believed by some that the security service was taking charge of the fight against the IRA. No such person or position exists, either in the police, security service or the Whitehall machinery to which they answer.
However, the deliberately low-key approach of his successor, David Tucker, to avoid the same problems, and the lack of any obvious impact from MI5, despite the Government's rhetoric that it would assist the fight against the IRA, has contributed to a sense of police powerlessness in the face of Warrington and Bishopsgate.
Supporters of MI5 stress that improving the intelligence base is a long-term process with results difficult to define or make public; opponents say they never expected much anyway since the main effect of the new arrangements is for MI5's teams of expert 'watchers' to be deployed on surveillance of suspects.
Many police officers believe the limit on publicly acceptable security measures which they can implement is close. Further increases, such as permanent security screens around city centres and Whitehall, together with regular road blocks on main roads would inevitably be seen as an IRA victory.
Professor Wilkinson argued that there were additional short-term measures available, such as more security cameras and more resources for police in the big cities. 'In the longer term we should be concentrating on the people at the top, the godfathers directing the campaign rather than the operational units who are simply replaced after arrest. Other countries manage to do this without resorting to internment, so why cannot we?'
Security experts recognise there is a particular problem policing the City of London, which has a large number of the type of Establishment symbols the IRA prefers to attack.
Owen Kelly, the City of London Police commissioner, has called for extended powers to tackle the terrorist threat. 'I want the power to set up road checks wherever and whenever, without specific reason for doing so,' he told a news conference. At present, police wishing to set up a road check must state a reason.
He defended his officers from any criticism, adding: 'If we were to guarantee that this could not happen, it would mean stopping and searching every vehicle coming into the City.'
The law would not allow it, the public may not stand for it and the force did not have the money and manpower to do it, Mr Kelly said.
Role of police and MI5 in fight against IRA comes under new scrutiny - Detectives hunt taxi gunmen