The Crown Estate has handed the Treasury less than half of what it returned a year ago, after the extraordinary offshore wind windfall that powered two years of record earnings began to wash out of its accounts.

The body that manages the monarch’s land and property portfolio, which also controls the seabed and much of the coastline around England, Wales and Northern Ireland, reported that the profit it passes to government to support public spending tumbled to £487 million in the year to March, down from £1.1 billion a year earlier. That is a fall of more than £600 million, and it leaves the public purse with roughly £500 million less than the previous year’s bumper handover once the swing in revenue is accounted for.

Operating profits told a gentler version of the same story, easing to £1.2 billion from £1.4 billion. The Crown Estate pinned the decline squarely on offshore wind, where a previous surge in income from option fees, the payments developers make to reserve a patch of seabed before they commit to building turbines, has faded now that those projects are moving into construction. Those fees had inflated earnings to record levels across the prior two years, a one-off boost the organisation has repeatedly warned would not last.

It is a reversal that had been well signalled. When the Crown Estate matched its record windfarm profits last year, it cautioned that the boom was temporary, with the option-fee income set to normalise as the leasing round progressed. The latest figures are the first to show that prediction arriving on the balance sheet.

Strip out the wind farm option fees, though, and the underlying picture looks rather healthier. The marine business lifted operating profits to £175 million, helped by favourable wind conditions, new offshore capacity coming online and expansion across the sector. The real estate and development arm grew profits to £258 million from £242 million, carried by the strength of London’s West End.

The value of the portfolio also moved firmly in the right direction. Net asset value rose to £16.7 billion from £15 billion a year earlier, reflecting a rebound in property values over the period. Over the past decade, according to the Crown Estate’s own figures, the business has returned around £5 billion to the Treasury in total.

The results land as the organisation gears up for a markedly more ambitious phase. After the Crown Estate Act 2025 handed it new borrowing and investment powers, granting greater flexibility over how it deploys capital, it has set out plans to invest up to £5 billion over the next decade across renewable energy, housing and science and innovation. That includes the next wave of seabed development, from the North Sea to the Celtic Sea, where it has already floated plans for floating wind farms capable of powering millions of homes.

Dan Labbad, chief executive of the Crown Estate, said the figures showed “both the strength of our underlying business and the importance of taking a long-term approach to managing national assets”. He added: “Over recent years, we have delivered strong growth for the country and invested in areas of national importance including renewable energy, housing and science and innovation.”

The challenge now is one of timing. The option-fee income that flattered recent results has done its job, drawing developers to the seabed, but the turbines themselves take years to build and the construction pipeline has not been without friction across the wider industry. Converting today’s leases into tomorrow’s recurring marine income will determine whether the Crown Estate can keep its contribution to the public finances from sliding further before the next generation of offshore wind comes good.