I was really a bit disappointed. It was published in 1985, and rather shows its age. While there is a lot of useful detail, the system of two to six page essays with (unnumbered and confusingly referenced) notes placed in the middle gutter is not in fact very clearly structured. To get a sense of the full sequence and significance of crucial political developments, your eye has to dart back and forth across the columns. Norman Davies succeeded with the much bolder step of having what are effectively full-page footnotes.
I also found that the material did not scratch my own itches, and did not really live up to the title. This is a history of England, with a fair bit of Scotland and nods towards England and Wales. History began in 45 AD for those parts of the larger island conquered by Rome; it begins in the twelfth century for the rest. There are some honourable exceptions - Patrick Buckland's piece on twentieth century Ireland is very good; Patrick Wormald (whose ex-sister-in-law worked for me years ago, in a bizarre bit of small-worldiness) brings the Celts into British history a bit ahead of the rest of the programme.
But my jaw really dropped when reading Keith Robbins' complacent framing essay for the entire twentieth century. On decolonisation, he writes "The French experienced defeat in Indo-China and Algeria and the Dutch in the East Indies, but the British beat a dignified retreat - if we are prepared to overlook Aden and Cyprus... There was no major upheaval in a colony close at hand comparable to Algeria in the case of France". I am not sure that Palestine or Rhodesia really qualify as 'dignified retreat' (one could also query the dignity of the British handovers in Kenya, Burma, and India/Pakistan). And I think there may also have been a British-ruled territory fairly close at hand whose internal upheavals had a certain impact on British politics. I accept that Algeria is very different from Ireland, but I think Robbins is lazy and dishonest not to even hint that there might be similarities.
The book closes with a historical Who's Who of (I estimate) about 700 individuals, of whom 50-ish are women and 40-ish are Irish. (And none Irishwomen.) I really think this must have been a bit outdated even in 1985.