What have we learnt since Britain's longest-serving Prime Minister of the 20th century passed away?

It has been frequently observed that the death of Baroness Thatcher has served as a reminder of how divisive a figure she was – either loved or loathed, adored or abhorred.

But however strong the passions which she arouses even today, it seems to me the most revealing things we have learnt since her passing are not about the late Prime Minister herself, or even how Britain feels about her, but about how we as a nation have lost our way in handling death.

There was a time, of course, when society had more recognised rituals that accompanied the passing of an individual: the shutting of curtains in a home, a vigil at the coffin – perhaps even the stopping of clocks. Then there was the bowing of heads and removal of hats in the street as a funeral cortege went past; a liturgy familiar to all in the country with its time-honed words ("in the midst of life we are in death"); a refusal to speak ill of the dead.

But nowadays, detached from our Christian moorings, and uncertain and confused as a society about the value of human life, we find ourselves all over the place. For many, it seems that anything goes: there were parties in several cities to celebrate Baroness Thatcher's passing; there has been chatter on the internet about pelting her coffin with lumps of coal; and of course there was the campaign to promote the song "Ding-Dong! The Witch Is Dead" – even if in the end it did only reach number two.

We have also seen a lack of restraint in what has been said. Former Liverpool Councillor Derek Hatton announced he would say "a million times" that he regretted the fact that Margaret Thatcher had even been born. MP George Galloway – of the ludicrously misnamed Respect Party – said: "May she burn in hellfires."

These words and deeds reflect more than simply the death of one particular and controversial individual. Underlying them is our drift from a Christian understanding of human beings. This has been expressed most clearly by atheist philosopher A.C. Grayling, who, commenting on Lady Thatcher's death, declared that "an outburst of pleasure at the departure of someone who was deeply polarising and gave expression to callous attitudes is both perfectly understandable and justifiable". He described respect for the dead as "an outdated and foolish principle".

From a Christian perspective, however, all human beings have infinite value because they are made in the image of God and yet are individually unique. However flawed and fallen they may be, they have an intrinsic worth which merits respect in life and also in death – from conception to the grave.

As a teenager, I remember being disconcerted when our school deputy head came out beaming to announce we should rejoice at the death of Soviet leader Leonid Brezhnev. No-one, of course, would want to be an apologist for his appalling mis-rule; nor is there any remote comparison in political terms between him and our former Prime Minister.

But he, too, was human. And all of us – including Mr Brezhnev, Lady Thatcher, A.C. Grayling, and yes, you and I – will one day have to give an account of ourselves to Almighty God. Jesus commands us to love both our neighbours and our enemies, presumably even in death – and he warns us that "everyone will have to account for every careless word they have spoken," (Matthew 12v36). At which point, too, it seems appropriate for me now to fall silent.