‘The IRA,’ said Patrick.

‘Yes. How did we beat them?’

‘You tell me, J.’

‘No. You try.’

‘Information. Intelligence.’

‘Correct. Where from?’

‘Eavesdropping, watching, moles, touts.’

‘Yes. What was the weakness the IRA had that our Islamist bomber brethren don’t?’

‘Pass.’

‘It was this. Despite all the attempts at cell structures and separate brigades, as they liked to call them, the IRA was at heart a centralised organisation. They had a unitary command. It was called the Army Council.’

‘Yes.’

‘Question. What makes any such group paranoid and ultimately destroys it?’

‘That it’s been infiltrated, I guess.’

‘Correct. Heard of Stakeknife?’

‘Yes, there’ve been stories about it. Bad stories.’

‘Idiot stories. I’ll tell you how it started. In the late 1970s I…’ J turned to Sara, catching her eye, ‘yes, that’s me, young lady… I was working with something called the Force Research Unit, FRU, in Belfast, when a Provo chappie walks in off the street one day. To cut a long story short, he says he’s had a fall-out and wants to get his own back. Worst mistake they ever made to rile him. He pretends to eat humble pie, rises and rises, eventually becomes a senior cog in their internal security apparatus – it’s charmingly known as the “Nutting Squad”. Over the next decade, he’s so successful in weeding out informers that he becomes its head. He’s also chief vetter of potential recruits. The electrical circuit of intelligence. Vets, recruits, cleanses. He convinces the leadership the organisation is riddled with spies. No future operation is safe. Best pack our weapons bags. Start of so-called peace process. Geddit, Patrick?’

‘Yes.’

‘That was my plan for friend Kareem. We called it Operation Pitchfork. Get that too?’

‘Mirror of Stakeknife?’

J spluttered again. ‘Nearly. Pitchfork. Pitch for K. K for Kareem. Geddit now?’

‘Yes, I get it. But you just said the Islamist threat wasn’t unitary.’

‘That was the whole bloody point. To make it like that.’ J wheezed, searching for air. ‘Kareem was perfect. His tendrils proliferated. So we offered him a job. To be our super-spy within British jihad. Like Stakeknife inside the IRA. From the end of 2005 till 2016 we had him in place. Tell me this. How many deaths were there from Islamist terror in the UK over that period? Just one. Right. That poor sod in Woolwich barracks. And what’s happened since? London, Manchester, jihadists lying in wait all over the country, security services overwhelmed. But then…’ There was a sudden gleam in his eye. ‘Then… Al Qaeda, ISIS, recruiters, fighters – they all bought into it. Kareem was their rising, internal star – a man with drive, charisma and access to money. He succeeded. He built an internal security unit to expose their traitors and informers. In fact, he was vetting the likely lads for us and telling us who the bad guys were.’

‘How could he convince them he was genuine?’ asked Sara.