OPINION:Looking at the histories of these islands in isolation and according to grand national narratives can be misleading; often, events focused on in one country have had effects in the other that are less obvious but no less real, writes JULIAN ELLISON

PEOPLE TEND to remember the bits of their history that glorify their own country. The difference between the English and the Irish is that the English choose to remember the good bits of their history, while the Irish prefer to remember the bad bits of theirs. Both are validating their current constitution and politics.

The best historians, meanwhile, earn their keep challenging myths through their research. English historians unearth reminders of a darker past, earning a reputation as cynics and begrudgers, while Irish counterparts get brickbats as revisionists for pointing out that not everything colonial was bad, or unearthing stories about the persecution of Protestants in Co Cork during the 1920s.

Historical truth is elusive. Ultimately, we ask why does it matter to put this or that slant on the past?

To answer this, let’s take a different slant on the old chestnut of British-Irish relations during the 19th and 20th centuries. Let’s ask not what Ireland gained by independence, but what did Britain – and Ireland – lose with the advent of the 26-county Free State and subsequent Republic?

We can look for evidence of Britain’s reputational loss on the international scene, and particularly within its empire, hastening the gathering pace of independence for many other countries, including India. However, what is often overlooked is the impact on internal British – and Irish – politics.

Irish independence led to the demise of the British Liberal Party. This is rarely admitted in British narratives. The Liberals had finally pushed through the Home Rule Bill in 1911 after 60 years of effort. Once this was achieved, the Irish Parliamentary Party never had any further impact on British politics.

The devastation of the first World War and the election of 1919 saw to that for good. With the demise of the Irish Parliamentary Party in Westminster, so went the Liberals’ secure ally in the campaign for reform.

Irish MPs had voted with the Liberals on issues that touched ordinary people and their ability to vote, to practise their religion, to experience the rudiments of social welfare, to have a government that was elected, where the political privileges of the elite were curbed or removed.

Once the Liberal Party could not call upon this block support from the IPP, it could never achieve government again, or move Britain forward in a sedate, principled manner. An urgent, radical, and confrontational Labour party recast politics as a class conflict.

In Ireland, republican politics ran in parallel – another expression of the militant ethos of the day. Ultimately, reactionary forces would bite back through that scourge of the left, Margaret Thatcher. Irish republican grandfathers helped provoke the British nemesis of their grandsons.

Cause and effect? It could also be said that Victorian and Edwardian Conservatives were responsible for the IRA of the 1970s and 1980s.

Thatcher’s predecessor as Tory leader 100 years before, Lord Randolf Churchill, was the calculating midwife to Carson’s Protestant unionism and the separatist six counties.

He intervened forcefully in Ulster politics to undermine the Irish Parliamentary Party. He played up the economic challenge to Ulster from independence, and helped bond the “Home Rule is Rome Rule” equation into loyalist consciousness.

In the middle of all this, the Liberal Party, supported by the Irish Parliamentary Party, achieved its greatest success in the reform programme of 1911, slashing the powers of the Tory House of Lords, and defining the pre-eminence of the elected House of Commons.

The failure of the Irish Parliamentary Party, and the Liberal programme of reform, means repeated Tory governments can cash in a historic debt from Ulster unionism in the Commons at times of slender majority. This will be true again.

Britain, and England in particular, may have lost its Liberal Party, but recovered its liberalism sooner than Ireland. Ireland is still divided, while Britain is still a United Kingdom, despite what Martin McGuinness used to say. It has divested itself of an empire, helped defeat Nazism and communism, received millions of immigrants, continues to reform its constitution, and its political parties fight for the centre ground. Where is the battle for the centre ground being fought between Irish unionist and nationalist politicians?

So, should Ireland join the Commonwealth? English people think it’s quite nice. Irish people think it’s a nonsense. Many Irish people in the North who share an English take on history think they belong to it already. Many Irish elsewhere would get pikes out of the thatch if the English queen were head of anything Ireland belonged to – turning out in great numbers at an emergency republican ardfheis in the Royal Dublin Society.

No, Ireland will only rejoin the Commonwealth when many other changes have happened first, not least that the people of these islands have a common honesty about the past, holding fast neither to the good nor bad bits.

The English are a long way further down this track than the Irish – probably because they don’t remember enough about the past to bother with it.

Their historical amnesia may mean they couldn’t tell you when, if ever, Ireland had a famine, and make the mistake of fighting yet another war in Afghanistan (is this the fourth or the fifth time?), but it also means they supported Ireland when they were going for the Grand Slam.

We have a long way to go to bring our past up to date. The challenge to admit and create a common history for our island still confronts us all. A divided past means a divided future, in Ireland as everywhere else.

Julian Ellison (44) studied classics and history at Oxford, but is now a technology entrepreneur in Co Mayo. His English mother was raised a Catholic, while his father is Church of Ireland from several generations of Irish astronomers and priests. British, yet republican, Irish, but “West Brit”, he believes that accepting a Protestant voice back into Ireland’s political and social culture should be the next phase of the peace process – and a prerequisite for a united Ireland