Devolution affected the politics of the United Kingdom's four constituent nations in fundamental ways.
Most obviously, the SNP were given - and seized - a huge electoral opportunity, and now run the show north of the border. Conversely, in Wales Plaid Cymru have gradually lost momentum while the Conservatives have steadily gained ground and trust. In Northern Ireland a power-sharing administration has emerged that few would have believed possible 20 years ago.
But it is in England that perhaps the largest change has occurred - and the main political parties have yet to engage with it.
In the late 1990s devolution was driven by a sense of grievance on the part of the UK's celtic fringes. Braveheart was translated into the modern age as a story of posh, rich English people suppressing and robbing 20th century Scotland. The stone of Scone should be returned, Scots Gaelic and Welsh should be re-established in schools and on the TV, and John Redwood should be forbidden from having political power west of the Marches until he learned to get his tongue round singing in Welsh.
By and large, the nationalists got what they wanted. Power was devolved, an Assembly and a Parliament were built, and Westminster politicans learned to butt out of celtic issues.
Only one place was never offered political or cultural devolution - England. In part this was because the devolution campaign was based in Northern Ireland, Scotland and Wales. In part it was because John Prescott and Tony Blair wanted to carve England into the European Union's preferred regions. In large part, we must assume, it was because Labour were unlikely to allow their Scottish-based majority to be undermined.
But just because England didn't get devolution, that didn't stop devolution from changing politics in England. In the last decade it is in England that a sense of grievance has been growing - financial grievance at having to subsidise the devolved nations to commission public services that England cannot afford, and political grievance at seeing Scottish MPs wield political power over English issues such as top-up fees.
A recent ComRes poll on the future of the union makes for interesting reading. On the most stark issue, that of Scottish independence, 36% of English voters want rid of the Scots altogether - around the same proportion as in Scotland. Where once there was a strong feeling that we were better off together, now only 21% of English voters think Scottish independence would make England worse off while 51% shrug their shoulders and think it would make no difference.
That is still a long way from a majority south of the border supporting Scottish independence, but on less radical proposals the resentment of English voters grows and grows. A YouGov poll for the Sunday Times last year found that 64% believe Scotland gets more than its fair share financially. 67% think Scottish MPs should be banned from voting on English matters - devolution in all but name.
Culturally, it's notable how the St George's flag has become not just acceptable but ubiquitous on houses, pubs and cars during major sports events where once it was rarely seen. The annual St George's Day concert in Trafalgar Square goes from strength to strength without any of the barbs about tweeness directed at the Last Night of the Proms. It seems the English have begun to learn from our celtic peers about celebrating our identity.
Our politicians are the only group who have almost entirely failed to notice and engage with this trend. Labour are bound by their strong Scottish base in the Commons to reject it, while the Conservative Party remain inexplicably wedded to their startlingly unsuccessful colleagues across the Border. The Lib Dems have a strong Scottish Commons contingent (for the moment, at least) which they cannot afford to alienate.
Some distant rumblings have begun, though. Labour radical and "Blue Labour" advocate Jon Cruddas told the Independent on Sunday recently that:
"Labour should have an 'English Labour'. It should embrace a modern, radical Englishness, or else England and patriotism will simply be a right-wing politics of loss and sourness."
At the weekend, Sir John Major floated the idea of fiscal devolution to Scotland and a cut in the number of Scottish MPs - something the Spectator's James Forsyth suggests might be an outrider operation for Number 10.
England was ignored in the original devolution settlement, and the main parties have been grindingly, achingly slow to pay any attention to England in the decade since. But English voters are developing an identity and an agenda with or without the politicians - and the parties must realise soon that there are millions of votes to be won or lost by engaging with this new English politics.