Unionist reaction: The Democratic Unionist Party leader, the Rev Ian Paisley, said the announcement by the chief constable vindicated not taking the IRA on trust alone during the recent negotiations.
"They must positively prove to everyone beyond all shadow of a doubt that all of their arms have been decommissioned, and that all of its illegal activities have ended for good," the DUP leader said.
"Their words no longer have any currency. Mr Adams's assertion that a republican can't be a criminal is as hollow as it is laughable.
"When we were engaged in the talks process, the (British) government informed us that Sinn Féin/IRA wanted to move towards ending its paramilitary and criminal activity. This is clearly not the case."
The party's deputy leader, Mr Peter Robinson, claimed the IRA's involvement in the bank robbery had raised the bar for republicans in the process.
"It was a clear and unambiguous statement from the chief constable which points the finger directly at the republican movement," said the East Belfast MP.
"They will not be able to dodge or duck the consequences."
It also causes problems for future DUP involvement in talks involving Sinn Féin.
"The implications of this, not just for us but others in the talks, are huge," a party source said.
"What this effectively means is that, at a time when Sinn Féin were talking to the British and Irish governments about an end to physical force republicanism, their colleagues in the IRA were planning this heist.
"It causes considerable problems for us.
"If we're to go into talks in the future involving Sinn Féin, what's to stop some people saying: 'When you took part in the process with them the last time republicans were secretly planning the raid on the bank'?"
The Ulster Unionist leader, Mr David Trimble, accused the Sinn Féin president, Mr Gerry Adams, of having "betrayed the prime minister personally".
A British government spokesman said: "The prime minister takes this development very seriously.
"He has made it repeatedly clear over the past two years that the political institutions in Northern Ireland can only be restored if there is a complete end to paramilitary activity by those involved, and that includes all criminal activity. He fully supports the chief constable in his efforts to bring those responsible for this major crime to account."