Rishi Sunak's suggestion that a "Stormont brake" could potentially block any new EU laws being introduced in Northern Ireland sounds very dramatic.

It suggests an "emergency handbrake" to put a halt to any new laws from Brussels.

The "brake" means the UK could veto any new EU laws to be applied in Northern Ireland if opposed by a majority of unionists or nationalists in the Stormont Assembly.

The European Commission's explainer states that the British government could - at the request of 30 members of the Assembly - veto the application of new EU legal provisions.

It stipulates that the mechanism can only be triggered "under the most exceptional circumstances, as a matter of last resort" and not for "trivial matters".

That sounds pretty straightforward. It seems that all it would take to apply the handbrake would be for 30 or more members of the Stormont Assembly from at least two parties to sign a Petition of Concern that would then trigger action by the British Government.

But the petition can only be signed if powersharing is restored.

British Prime Minister Rishi Sunak

The Windsor Framework states that the Stormont Executive must be operational, including having a First and Deputy First Minister in post, and must be "in regular session".

So, the DUP would have to agree to restore powersharing to have access to the brake.

Then comes the question of what happens after the Petition of Concern becomes active.

The Framework states that the mechanism is "without prejudice to the status of cross-community voting and safeguards in the 1998 Agreement which apply solely and exclusively to devolved matters".

It also references the New Decade New Approach agreement which formed the basis for the restoration of the Stormont Assembly after a three-year suspension in January 2020.

The NDNA states that a 14-day consultation period would follow the triggering of a Petition of Concern and there would then be a vote in the Assembly.

DUP leader Jeffrey Donaldson

Under the voting rules in Stormont, this would be a cross-community vote that would require the backing of a majority of nationalist and unionist Assembly members.

On that reading, if in the future the EU wants to apply new regulations in Northern Ireland, the Stormont Assembly would have to give its consent to diverge from regulations that apply in the rest of the UK.

If the DUP objected to the planned new laws,it would trigger a Petition of Concern and the gathering of the signatures of 30 or more unionists would mean there not be a majority of unionists in favour of divergence and that would then trigger an intervention by the British government.

But the DUP view is that this is a very different mechanism and that the triggering of a Petition of Concern with the 30 required signatures would trigger an immediate referral to the British government with a request for it to veto the EU law in question, with no vote in the Assembly.

A brake on the proposed law would be applied immediately while the UK considered its response.

If the UK was to agree and decided to veto the law there would be engagement with the EU, which has insisted the European Court of Justice will be the final arbiter in any legal dispute.

So does that mean the ECJ could veto the veto?

These are issues the DUP and other Stormont parties are likely to want clarified.

The devil will be in the detail of the underpinning legal text on the issue.

"What happened today is that the foundations have been dug, and in the future the legal text will provide the concrete for those foundations," explained a senior DUP source.

"Until the concrete is poured, the foundations will not provide the basis to rebuild a stable power sharing government.