There are some stories about notable people that must be called "obituary fillers". These stories are so memorable or significant that obituary writers add them to the partially written accounts of the still living, adding any dramatic new developments as they go along. Before Iraq, Tony Blair must have hoped for a draft of his life that focused on his landslide victory in 1997; now it is impossible to imagine an obituary that isn't dominated by his decision to go to war.

Judging by the reaction to the revelation that Michael Heseltine had throttled his mother's dog, which came hard on the heels of news that he had shot 350 grey squirrels, anyone would think that the obituary writers would be scrambling to their computers to change the subtitle of the Conservative peer's account from "Tarzan who wielded knife but never wore the Tory crown" to "Evil dog killer who shot squirrels for fun". Before this week, Lord Heseltine's most famous contribution to politics was his failure to become prime minister after helping to topple Margaret Thatcher. But now what?

The reaction to Heseltine's "confession" in Tatler, which he later clarified in an interview with the BBC to mean that he hadn't actually killed Kim the Alsatian but pulled the lead tightly around its neck after it had bitten him, tells us how the "nasty Tory" label is still potent. Despite years of attempts by David Cameron to detoxify, despite claims by Theresa May that her "nasty party" comment in 2002 no longer applies to the tribe she leads, the tag still lingers.

Unlike poor Kim, who had to be put down the next day, it refuses to die. It doesn't help that Heseltine is posh, with an estate that may be plagued by grey squirrels but nevertheless sprawls over 70 acres. Social media is awash with confirmation bias at the best of times, so the only way Twitter could respond to this shaggy dog story was with a mixture of outrage and glee.

The irony is that Heseltine has done more to detoxify the Conservative Party than most. After the Toxteth riots, when the Thatcher government was set on condemning Liverpool to "managed decline", the then Environment Secretary saw that revitalising the city would help the whole country. In a forerunner of the Northern Powerhouse, Heseltine recognised that regeneration in northern cities was essential to boosting the entire UK economy – which was why George Osborne appointed him as a treasury adviser on industrial strategy.

His combativeness and ruthlessness while a Cabinet minister may fit his 'Tarzan' label – in 1976 he grabbed a 5ft-long silver club from a House of Commons' table and brandished it at Labour MPs – however, as a One Nation moderniser before Cameron had even entered Parliament, Heseltine is the godfather of Cameronism. He is not a "nasty Tory".

Of course, what Heseltine did to the Alsatian was abhorrent. As the RSPCA says, dogs who bite need to be taken to a behaviour specialist, not throttled. But the incident needs to be placed in the context of its time, more than 50 years ago, and place – Heseltine's pregnant wife was also in the house when the dog flew at him, biting him on the hands. This incident should not overshadow Heseltine's contribution to politics. Perhaps, when the time comes, it should be a footnote in his obituary, but nothing more.