If geopolitics could be compared to a grade school playground, the United Kingdom has long been America’s best buddy. Our two militaries have worked side by side in countless conflicts and likely will continue to do so for years to come. So when the Royal Navy loses one of its most important offensive and defensive capabilities in one fell swoop, we should stand up and take notice.

For years now, the Royal Navy has been armed with American-made Harpoon anti-ship missiles. These missiles provide each vessel with a powerful method of engaging other warships even before they appear on the horizon. With an effective range of 80 miles, these ship-fired missiles can deliver a 488-pound high-explosive warhead directly into the hull of an enemy vessel. Battle tested against Iranian and Libyan navies in the 1980s, the Harpoon has become a staple of the Royal Navy’s warfighting capabilities. That is, until now.

The missiles the U.K.’s Navy currently has in service are set to expire in 2018. Current naval expenditures don’t account for funding a replacement, which will leave the British Navy without any other means of engaging enemy ships besides their 4.5-inch deck guns. These British-made semi-automatic guns aren’t to be dismissed, with their high-explosive rounds, limited personnel requirements, and range of 17 miles, but when compared to the effective range of the Harpoon missiles they’ll have to replace, they leave a 63-mile gap in the radius of each ship’s former offensive and defensive strike capabilities.

This news comes only months after Russia announced that their new anti-ship missiles, capable of hypersonic speeds and a range of 180 nautical miles, will go into production in 2018, the very same year the Queen will find herself without a single anti-ship missile in her fleet’s arsenal. Seventeen miles is a significant range to be able to fire explosive rounds, but the likelihood of naval battles being carried out in such a manner as to actually be able to use these guns grows less likely as each nation’s naval technology continues to advance. The days of broadsiding your opponent with a flurry of cannonballs has long been left behind, in exchange for satellite-guided missiles with fire-and-forget capabilities.

The Royal Navy would likely never even engage an enemy ship. With such a significant difference in ranged weapon capabilities, it wouldn’t be difficult for most nation’s naval vessels to just remain outside of the deck guns’ range. A British frigate or destroyer would likely have to somehow repel an enemy ship’s full payload of anti-ship missiles before ever having a chance to fire a single round. In order to effectively engage a Russian Neustrashimmy-class frigate, a British naval vessel would have to close a 51-mile gap, wherein the Russian frigate could unload a terrifying eight Russian missiles with 320-pound explosive warheads before the former was even able to target their enemy.

The Royal Navy does intend to field their new Sea Venom missiles during this gap in capabilities. The Sea Venom, however, is an anti-ship missile intended for use engaging fairly smell vessels. The missiles are equipped with 60-pound warheads and will be fired from Wildcat helicopters once fielded in 2018. Unfortunately, due to their relative size, Sea Venom missiles would do fairly little damage to any ship the size of a Russian frigate or larger.

The issue, it would seem, is funding. Most of the Royal Navy’s budget is currently tied up in the development of two new Queen Elizabeth-class aircraft carriers and their new Dreadnought-class missile submarines. As a result, funding to equip existing vessels with new anti-ship missiles may not be forthcoming for at least a decade.

With recent incidents like the Russian Navy passing through the English Channel en route to Syria, with the British Navy closely shadowing them, and tensions increasing with China in the South China Sea, future altercations between military powers would likely occur between navies rather than ground troops—at least at first. As the Crown’s primary ally, it may fall to American vessels to provide the brunt of both nation’s naval defenses in such a hypothetical scenario.