The legacy of Tony Blair is a many-splendored thing, as any passing Labour MP will doubtless tell you, assuming they can be persuaded to take a break from intoning “Ooooh Jerr-a-meee Corrr-bin” in the hope of avoiding the coming purge.

It is twenty years since Blair was elected as Prime Minister of the UK and ten since he stepped down but he still casts a long shadow. It would be churlish to deny that he left behind a country that was more tolerant and at ease with itself than the one he inherited but he had his failures too, and not just in Iraq. In terms of sheer carelessness, it would be hard to beat his willingness to commit random acts of constitutional vandalism, the effects of which haunt our political system.

Like most human customs and institutions, the British constitution evolved over time through a series of crises and compromises, fudges and fixes. But it was remarkably resilient and flexible and hadn’t been seriously amended in the best part of a century. It was typical of New Labour hubris that they thought they could create a better one. As history shows, there are few things as prone to malign unforeseen outcomes as grand plans to “improve” the governance of a country and Blair’s reforms were no exception.

For example, a hereditary House of Lords may well have been indefensible but that didn’t really matter so long as no-one attacked it – it worked in practice even if it were impossible to see how it would work in theory. However, Blair was determined to reform it; out went a careful revising chamber aware of its precarious legitimacy and in came a retirement home for defeated politicians, dripping in patronage and bristling with militancy.

Similarly, the position of Lord Chancellor, extant since the Norman conquest, was earmarked for abolition after what must have been a particularly long lunch. In the event, it proved much harder to get Jack Straw out of stockings than anyone in government had anticipated.

Worst of all, though, was the ill-considered devolution settlements, particularly the casual indifference to the relationship between the devolved administrations and the House of Commons.

In 1997, as for the previous 30 years, Labour dominated Scottish and Welsh politics and the devolution settlement was designed to entrench that hegemony, a bulwark against future Tory governments. The Northern Ireland Assembly had a more noble birth, created as part of the Good Friday Agreement. Stormont convened in 1998 while the National Assembly for Wales and the Scottish Parliament followed in 1999 but the status of Scottish, Welsh and Northern Irish MPs was unchanged.

Tam Dalyell had spotted the problem back in 1977:

“For how long will English constituencies and English Honourable members tolerate … at least 119 Honourable Members from Scotland, Wales and Northern Ireland exercising an important, and probably often decisive, effect on English politics while they themselves have no say in the same matters in Scotland, Wales and Northern Ireland?”

Far from searching for a bold and imaginative answer to the West Lothian question, the Blair government pretended it had never been asked. It seems that the mere creation of the parliaments was more important than their ongoing role. This is further evidenced by the fact that few of the Scottish Labour “big beasts” were willing to take the high road back to Scotland. Gordon Brown, Robin Cook, Alistair Darling and George Robertson all stayed in Westminster. Only Donald Dewar returned home, earning the laughably grand soubriquet “Father of a Nation”; truly a Caledonian Kemal Atatürk.

While Labour was simultaneously in government in Westminster, Holyrood and Cardiff, crises were avoided. The huge majorities that Blair had won in England helped – Labour could have passed virtually all domestic English legislation without requiring the votes of Scottish MPs (except, notably, for the introduction of university tuition fees in England and Wales).

The first signs of danger occurred in 2007 when the SNP formed a minority government in Holyrood (dependent on Conservative and Liberal Democrat votes, not that anyone seems to remember) but it was a somewhat cautious administration, eager to demonstrate that they could govern effectively.

However, in 2012 the SNP formed the first majority government in Holyrood’s history and adopted their now-familiar swagger. By this point Labour had been replaced by the coalition government and David Cameron rightly acknowledged that they had won the right to hold a referendum on independence, but bafflingly allowed them two years to make the argument, nearly losing it in the process.

In the 2015 General Election, the SNP swept all before them on a tide of frustrated nationalism. The Tories realised mid-campaign how poorly the idea of SNP MPs supporting a Labour government was being received in England and won a slender majority on the back of it. Theresa May promptly squandered this majority in 2017 and brought a Labour-SNP coalition within sniffing distance of government. Only a deal with the DUP has secured her government’s position.

Two points emerge; first, it was rash in the extreme of David Cameron to adopt the campaigning position that Scottish MPs shouldn’t be allowed to determine the next government – what are they there for if not that? For precisely the same reason, it is absurd of Labour and the SNP to criticise the recent Tory pact with the DUP. Aren’t all MPs equal? Or are some more equal than others?

Second, the Middle England Threat Level might have reached “somewhat miffed” had Ed Miliband become Prime Minister with SNP support, but there’s little doubt that a Corbyn government would have raised it to “really rather cross”. Imagine Scotland being shielded from the excesses of a Corbyn government while its MPs voted to sustain it.

The Conservatives have another immediate problem. Many would dearly love for Ruth Davidson to be the next Conservative leader – and with good reason. Few people have articulated and embodied modern, tolerant conservatism better than she has. But for her to be leader, and potential Prime Minister, she would have to be an MP – and almost certainly an MP for an English constituency.

For how could a Scottish MP lead a government whose programme of domestic legislation wouldn’t apply to Scotland? The most prominent Scot in the cabinet is Michael Gove, who was the MP for Surrey Heath but only after having lived in London for many years. Ruth Davidson has built her life and career in Scotland. Even if she was willing to move, being parachuted into an English constituency would ruin her authenticity, a rare commodity in politics. Still, the fact remains that an English MP would have more legitimacy as Prime Minister than a Scottish MP, no matter how talented.

The ambiguous status of MPs from Scotland, Wales and Northern Ireland cannot last. The Prime Minister should be the person that commands the confidence of the House of Commons but that is no longer the case. The leaders of the DUP and the SNP sit in Stormont and Holyrood respectively, their MPs mere delegates. Even the Scottish Conservative MPs seemingly owe greater allegiance to Ruth Davidson than to Theresa May. To be sure of carrying the house, the Prime Minister must negotiate with people in other legislatures, a poor situation to be in.

Is there a solution? A possible compromise might be that Scottish, Northern Irish and Welsh MPs should sit respectively in the Scottish Parliament and Irish and Welsh Assemblies, with those parliaments topped up via an additional member system as at present. For UK-wide matters, the MPs would sit at Westminster. Taking things to their logical conclusion, should English devolution progress, all MPs would sit in their own regional assemblies and return to Westminster as required. Why shouldn’t London MPs sit in the London Assembly? The respective secretaries of state would simply be the governing party’s leaders in those assemblies. Given that Ruth Davidson is frequently challenged on UK government policy (e.g., the so-called “Rape Clause”), she might as well officially represent that government.

In any event, it would enliven Westminster politics considerably if Nicola Sturgeon, Ruth Davidson, Kezia Dugdale, Arlene Foster, Leanne Wood and Carwyn Jones all sat in the House of Commons together.

No matter the proposed solution, there would doubtless be problems. It seems that the Blair botch-job urgently needs some sort of remedial surgery. But then, perhaps just waiting for the inevitable crisis to happen before applying an emergency fix would be in the best tradition of the British constitution. Maybe we should learn from Blair’s mistakes and just leave the damned thing alone.