SHIPS attacked by pirates in the Red Sea? Gladstone or Disraeli would never have allowed it. Not on their watch.

In those days, the Royal Navy took seriously its duty to be a ­“security for such as pass on the seas upon their lawful ­occasions”. Despatching a cruiser or two, it would have made short work of warring Arab tribesmen threatening to hold the world’s trade to ransom.

The Red Sea was as imperially British as the Thames. This vital trade corridor was guarded at one end by Egypt and at the other by Aden, both British protectorates. Their lands were held by the British Army, and their peoples ­administered under British tutelage, not for any intrinsic value that these countries had, but ­simply for their strategic importance on the flanks of the sea lanes to India.

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The same was true of the Mediterranean. It was a British sea from one end to the other. The British naval base at Alexandria guarded Suez (below). Gibraltar locked the other door. In between, Malta and Cyprus meant that a British ship was never far from a Union flag, a safe coaling ­station, and a telegraph link to London.

The National: FILE - An army zodiac secures the entrance of a new section of the Suez Canal in Ismailia, Egypt, Aug. 6, 2015. Cash-strapped Egypt increased transit fees Tuesday, March 1, 2022, for ships passing through the Suez Canal, one of the world’s most

Britain left India in 1947. It was kicked out of Egypt in 1956 and withdrew from Aden in 1967. For some Tory-voting boomers, that is still within living memory. In geostrategic terms, however, it is another age. Britannia ruled the waves in another world, a world that has long past.

Left and right love to argue about the nature and legacy of the British Empire, but the truth both must acknowledge is that it is over. We ­cannot live in that past.

Simon McDonald, a former permanent ­secretary at the Foreign Office, has ­recently ­published a book (Beyond Britannia: ­Reshaping UK Foreign Policy) in which he argues that the UK should retreat from its great power ­delusions by, amongst other things, selling off aircraft ­carriers, abandoning the nuclear ­deterrent, scaling back the Royal Navy, and a giving up the UK’s permanent seat on the UN Security Council.

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This has met with the usual howls of scorn from right-wing columnists. “How dare a former senior Civil Servant and, in effect, the UK’s top diplomat, hold such outrageous views?”, they thunder.

Perhaps McDonald offers the kind of glimpse of reality that is woefully lacking in our ­politics. The UK is no longer a world power. It is not ­impressive to pretend otherwise; it is ­embarrassing, sad, tragic.

This was obvious by the 1970s – at a time when the Royal Navy was still the third largest in the world, and when the British economy was many times the size of that of China.

But now we – the British political class, at any rate – have returned to unreal thinking, to a fantasy of greatness. To imagine Britain in any terms other than greatness is seen as ­treacherous.

The UK must, in politician-speak, always be “world-leading” and “world-beating”. Okay, fine. We have world-leading domestic energy costs and world-beating shit in the rivers. I would ­settle for “adequate”.

The historian Dominic Sandbrook joins the dots between Brexit and the “Falklands Effect”.

The National: Port Stanley in the Falkland IslandsPort Stanley in the Falkland Islands

Just when the UK was coming to terms with its post-imperial status, and recognising that its future lay in Europe, the Falklands seemed to demonstrate that British hard power was not yet dead. We could still (just about) ­muster a taskforce and conduct remote ­amphibious operations to restore a British ­governor on an island in the far seas, just like old times.

Now we live with the consequence of ­delusion: Brexit. Cut off from Europe, our ports under self-imposed blockade, trade declining, real wages falling, and poverty rising.

Britain needs a metaphorical slap to bring it to its senses. If it is to salvage anything of worth, it has to stop living in the sepia-toned ­dreamworld of a halcyon imperial past and face the grim reality that confronts us.

Facing that reality is hard because British state is an imperial state, created by and for ­empire. The UK’s continued existence makes no sense in a post-imperial world and an ­integrated ­Europe, and so, to keep the UK ­together, we must live in a nonsense world, where ­English wine in pint-sized bottles is paraded as a ­ success story.

The UK seems persistently incapable of ­reforming itself to become a normal European country, which would require, as a minimum, a proper modern written constitution. That is because it is not one country, but an imperial union of four countries. Any reform that denies that national plurality is bound to fail.

Perhaps it would be different for an ­independent England, shorn of its imperial ­delusions. It would certainly be different for an independent Scotland and Wales.

As we face the New Year, remember this: ­Scottish independence is just the next step in the unravelling of a British imperial state in ­terminal decline.

The sooner we get out, the better.