Plans for a third crossing over the Menai Strait are to be revived, with the Welsh Government saying work will restart immediately on developing a new route between Anglesey and the mainland.

The decision is likely to be welcomed by communities and businesses across Ynys Môn and north Wales, where the vulnerability of the existing crossings has become increasingly apparent in recent years.

The Welsh Government says the key issue is resilience. The two existing crossings effectively operate as a single transport system, with the Britannia Bridge carrying the majority of traffic but vulnerable to high winds, while the historic Menai Suspension Bridge has lower capacity and has required significant structural work and restrictions.

When either crossing is restricted, the consequences can be felt far beyond Menai Bridge itself, with congestion spreading along the A55 and into communities on both sides of the Strait. Previous closures have caused disruption for commuters, businesses, freight operators, tourists and emergency journeys.

That vulnerability was starkly demonstrated by the problems affecting the Menai Suspension Bridge last year, when structural defects led to severe restrictions and a temporary closure. The experience highlighted the difficulty of relying on two ageing crossings when one is unavailable.

There is also a wider economic argument.

The A55 is the principal east-west transport artery through north Wales and provides the main road connection to Anglesey and Holyhead. The crossings are therefore important not just to people living around the Menai Strait, but to freight, tourism and businesses across the region and to the movement of goods to and from the port.

Previous Welsh Government work has identified the importance of the crossings to the wider North Wales economy, while the North Wales Transport Commission heard particular concerns about the impact that poor resilience could have on the Port of Holyhead, tourism and future economic development on Anglesey.

The case has arguably become more significant as Anglesey looks towards future economic and energy developments. Welsh Government ministers have previously acknowledged a strong case for considering the long-term need for another crossing because of the strategic importance and age of the existing infrastructure.

However, building a third crossing would not be without its challenges.

The Menai Strait is an environmentally and historically sensitive area, and any new bridge or associated road infrastructure would need to take account of its landscape, habitats, wildlife and communities. The Welsh Government says the revived development programme will include environmental assessment alongside design work, business case development and the statutory approvals that would be required before construction could begin.

There are also questions about whether building additional road capacity should be the sole answer to transport problems. The North Wales Transport Commission has highlighted the need for better public transport, walking and cycling provision and a wider approach to reducing reliance on the car. Any new crossing therefore needs to be considered as part of the wider transport network rather than simply as another road.

For the moment, the Government is proposing a combination of long-term and immediate measures.

Development work on a third crossing will restart, while investment will continue in maintaining the two existing bridges. Practical measures on the Britannia Bridge will include wind deflectors, variable speed limits and other operational changes intended to reduce the number and impact of weather-related disruptions.

The Government has also ruled out a three-lane tidal-flow arrangement on the Britannia Bridge after evidence identified significant safety and operational concerns.

The announcement represents a change in direction after the previous roads review recommended that a third Menai crossing should not proceed in its then-current form. A protected route for a future crossing remained in place, however, while subsequent work examined how resilience could be improved.

The Welsh Government has now decided that development work should begin again.

The separate announcement concerning the M4 around Newport is considerably further south and is a much longer-term piece of work. The Government is commissioning an 18-month study of possible road-based solutions around Newport, alongside public transport, junction and network-management measures.

For north Wales, though, the significance of today's announcement is much closer to home.

A third Menai crossing would not remove the need to maintain the Britannia and Menai Suspension bridges, nor would it solve every transport problem on Anglesey. It would, however, potentially give the region something it currently lacks: a third route across one of the most important and vulnerable points on the North Wales road network.

The next stage will be to establish whether a new crossing can be designed and delivered in a way that provides that resilience while protecting the exceptional environment and communities around the Menai Strait.

For Anglesey and north Wales, the debate has now moved on from whether a third crossing should simply be discussed to the more practical question of what it should look like, where it should go and how it can be delivered.