PASSIONTIDE’s darker themes, re­­lating to religious hatred and viol­ence, found expression in Isis and the Battle for Iraq (Channel 4, Thursday of last week). The Iraqi army is defeating IS, but only with the considerable help of Shia militia groups — some 40 of them.

So powerful are these groups that the government can do nothing to temper their excesses. For, although they are united against a common enemy — the loathed Daesh, or IS — the Shia also hate Sunnis, and consider that most Sunni males might as well be Daesh fighters. As each village is liberated, the men are separated off, and, in many cases, never seen again.

Ramita Navai presented a com­pelling documentary, in the thick of fighting, just outside the prisons in which nameless terrors were being inflicted, and in the refugee camps (three million Iraqis are refugees in their own country), sitting with dis­tress­ing mothers and wives, inter­viewing generals and poli­ticians.

The local, self-interested point is that these militias are as good as our allies, fighting with weaponry whose supply we condone: and that the hatred that they are stoking up will surely, in the future, create a civil war, with consequential terrorism worldwide.

Getting religion out of the way before Holy Week, Mary Magda­lene: Art’s scarlet woman (BBC4, Thursday of last week) was an art-historical exposition of depictions of the Apostle to the Apostles; but, as it was devised and presented by Wal­demar Januszczak, it was at once knock­about buffoonery and also theo­logic­ally informed explora­tion.

He pointed out how meagre the actual references to her are in the Gospels, and how unfounded the elision is between her and the prosti­tute who broke her jar of precious ointment over Jesus’s feet. This cre­ated a figure that appealed to artists throughout the centuries. The un­­founded legend of her miraculous journey to Provence, and cave-bound years of penitence, could have en­­gendered more severe con­demnation: the Church was eager to have pictures that simultaneously depicted naked female flesh while also showing her spending years of bitter contrition.

Such images are hypocritical and sadistic: we want to revel in the de­­lights of the flesh, and also be pun­ished for them. Never mind Jesus’s forgiveness: she should jolly well suffer for daring to live out our own desires.

In How To Be A Surrealist with Philippa Perry (BBC4, Tuesday of last week), the psychotherapist Phil­ippa Perry gave a deceptively light­hearted account of the Surrealist move­ment, finding valuable aims in its desire to un­­­cover the subconscious and draw from the creativity hinted at in our dreams, without conscious aesthetic control.

Surrealists thought that tradi­tional ways of thinking had led to the horrors of the First World War; so this was a proper line to explore, seeking a deeper, surreality beyond mere consciousness. It was origin­ally not a style, but a philosophy.

I truly want to like Decline and Fall (BBC1, Fridays), and yet it fails to live up to Waugh’s wicked glee at the discomfiture of the innocent. It needs more pace and urgency, a more preposterous Dr Fagan, and the white-slave-trade plot less explicitly signalled. It should, alas, be more vindictive.