Duncan Manning, a Business Opportunity Manager on Brent Decommissioning said removing the 300,000 tonne legs would be “riddled with safety risks” and held little benefit to the environment.

Mr Manning also advised that only the upper part of the Alpha platform’s jacket would be removed as it was too heavy to be removed in one piece.

Shell also has plans to leave behind other equipment such as the heavy pipelines which are entrenched in the seabed, along with drill cuttings and storage cells.

Mr Manning conveyed disagreement within their stakeholders stating that there was “no one size fits all solution” and that Shell’s plans had “generally” been accepted by stakeholders.

Shell’s plans to submit its decommissioning proposals to the Department of Energy and Climate Change (DECC) come after nine years of research and over 300 consultations.

The Brent field has been a huge contributer to the oil economy having produced oil for the past 40 years, however it is now one of the most complex engineering projects of its kind, with 4 platforms, 140 wells, 64 storage shells and 28 pipelines to decommission, it is expected to take a decade to complete.

Mr Manning also confirmed that Allseas’ giant crane ship (the Pioneering Spirit) would now be set to lift the Brent Delta topside in early 2017, a 6 month delay from the original date due to the need for strengthening of the vessels lifting arms.

If the DECC approves Shell’s plans, the permission to leave the structures behind must still be granted by Ospar, an organisation which was set-up to protect the marine environment of the North Sea and Atlantic Ocean.

Installations must be removed in their entirity once they reach the end of their lifespan according to Ospar rules, but Mr Manning is hopeful Ospar will make an exemption for Shell as it has done in the past for other operators.

Mr Manning drew attention to previous examples of legs from older platforms being left at sea, adding that beacons are attached to the structures in order to prevent collisions with ships. He stated “very little of what we do is setting a precedent, much of it has already been done by another operator”.

“Ultimately, it’s up to Ospar to approve or turn down our proposals. Ospar says companies should aim for a clean seabed, but it is pragmatic enough to understand there are big challaenges associated with removing infrastructure”.

“A clean seabed does not always make sense – there are even some benefits associated with leaving things in place. The amount of carbon dioxide needed to conduct offshore activity has to be taken into account”.

Mr Manning said it could take a year for DECC and Ospar to decide whether to accept the proposals.