Theresa Villiers is Secretary of State for Northern Ireland and MP for Chipping Barnet.

Last September at the Party Conference I announced that the Government had made a realistic assessment that the time was right to convene a new round of cross party talks in Northern Ireland. The aim was to address some key issues hindering the effectiveness and credibility of devolution and the Stormont Executive.

The talks began at Stormont House on 16th October. As a signatory to the Belfast Agreement, the Irish Government were fully involved in all those matters where they have responsibilities, consistent with the long standing “three stranded approach”. This provides that internal arrangements for Northern Ireland are a matter for the UK Government and the NI political parties alone.

On 23rd December, following a marathon 11 weeks of negotiations, including a final 30 hour stretch, we presented the Northern Ireland Executive parties with a final heads of agreement document. This reflected the many hours of discussion and had the input of both the UK and Irish Governments.

Key issues covered include the finances of the Stormont Executive, reform of the devolved institutions and the legacy issues of flags, parading and the past.

Taking each in turn, the Agreement sets a path for the Executive to put its finances on a sustainable footing for the future, averting the impending budget crisis which was threatening the stability and future viability of the devolved institutions. This includes the nationalist parties agreeing to the implementation of welfare reform – with certain agreed adaptations paid for out of the Northern Ireland block grant – alongside efficiency measures and wider reforms to the public sector.

Measures to improve the way the devolved institutions work include provision for an official opposition for parties who choose that option rather than taking up a ministerial position.  My colleagues Lords Lexden and Empey have been particularly active on this issue which has strong Conservative support and was in our 2010 manifesto. There is agreement on a reduction in the number of Assembly members by 2021 and also on cutting the number of government departments.

On flags and parading, a Commission on Flags, Identity and Culture is to be established by June. Based on party leader discussions which took place in the summer, proposals are set out by the Government which open the way for a devolved system of adjudicating parades to replace the Parades Commission.

Crucially, the Agreement also sets out broad ranging new structures to deal with the legacy of Northern Ireland’s past. These include an Oral History Archive, a new Historical Investigations Unit to look at the deaths that occurred as a result of the Troubles, and an Independent Commission for Information Retrieval established by the UK and Irish Governments.

All of these bodies are required to operate in a fair balanced, proportionate, transparent and accountable way. This will prevent any group or strand of opinion from being able to subvert the process or re-write history – something that we Conservatives have always been adamant we would not tolerate. The new system puts the needs of victims and survivors of the Troubles at its heart and has reconciliation as a key goal.

Consensus on how to deal with Northern Ireland’s past has eluded successive governments since the Belfast Agreement was signed 17 years ago, as it did Dr Richard Haass in the talks he chaired at the end of 2013. So the significance of what this Conservative-led Government has achieved should not be underestimated.

For our part the Government has agreed to contribute £150 million over five years to help fund the structures dealing with the past. This means that crucially the PSNI can devote their efforts to policing the present rather than the past.

This forms part of a wider package of financial support from the Government which is made up of a combination some new funding and important flexibilities in relation to existing resources. The package is targeted at costs resulting from Northern Ireland’s specific circumstances: the legacy of its past; its divided society; and the overdependence of its economy on the public sector.

The Agreement also paves the way for legislation to devolve the power to set the rate of corporation tax for Northern Ireland. There is strong support for this change across all five of the parties in the Northern Ireland Executive and the business community. Given the land border shared with a lower corporation tax jurisdiction, this measure has the potential to create thousands of new jobs and stimulate crucial growth in Northern Ireland’s private sector, leading to a stronger, more balanced economy.

I welcome that fact that we Conservatives are delivering this momentous and potentially transformative change (subject to the important conditions contained in the Agreement on putting the finances of the Northern Ireland Executive on a stable basis). I pay tribute to my predecessor, Owen Paterson, who picked up this issue in Opposition, championed it, and put it firmly back on the political agenda after it had been dumped by Gordon Brown.

The Stormont House Agreement involves compromise on all sides, including from both the UK and Irish Governments. It is fair and balanced – and it has been widely welcomed.

But of course securing an Agreement is not the end point, far from it. For example, there are many important questions still to resolved on flags and parading. Much work will be needed to get the Agreement implemented, from the NI Executive, the UK Government and, where appropriate, the Irish Government. I can give this assurance – unlike our Labour predecessors this Government will implement our side of the Agreement faithfully and fairly. There are no side deals.

I believe that the Stormont House Agreement represents a genuine and significant step forward for Northern Ireland, which offers the prospect of real progress on some of the most intractable issues we face there.  These are problems that have defied multiple attempts to resolve them over the years.

This Agreement gives the five parties in the devolved Executive chance to refocus and work together with renewed confidence for a more prosperous, more stable, more united and more secure future for the people of Northern Ireland.  I am urging them all to seize the opportunities it presents to build a brighter, more secure future for Northern Ireland.