‘So…’ concluded Morahan that evening, after explaining the Prime Minister’s invitation to his wife, Lady Iona, at their Chelsea home. Like him, she was a public figure; née Chesterfield – which she’d kept as her professional name – she had risen to be Head Mistress of a prestigious London girls’ school and one of the country’s most formidable educationalists.

‘So indeed,’ she replied, looking beyond him.

He inspected the fine bone structure of her high-cheeked face, the still creamy glaze of her skin, the dark brown hair expensively laced with auburn tints – and, as so often, found it hard to interpret what was going on within. Was she even thinking about what he had told her? She might just as easily be hatching some new scheme in the compartmentalised lives they had become accustomed to living.

‘Do you have a view?’ he asked.

Her eyes shifted to engage his. ‘The obvious one. If you scrutinise the security services, it may – probably will – bring their scrutiny onto you.’

‘Yes.’ He paused. ‘That has been the main focus of my thoughts.’ He stood and walked over to the drawing room triple window, resting against its ledge. ‘Perhaps I’ve reached that stage of life when one can no longer be cowed.’

‘In that case…’

‘Put it this way,’ he interrupted. ‘I agree with the Prime Minister. It should be done. The intelligence services failed us in 2003—’

‘Isn’t that harsh?’

‘They should have stood up to Blair instead of kowtowing. The blame was theirs too.’

‘Some might say we’ve moved on from then,’ she said softly.

Was she offering him, if at heart he needed it, a way out, an escape from the trap door? It steeled him. ‘Sandford’s right. We need to see inside them.’

‘If they let you.’ The softness had gone.

The next morning, Sir Francis Morahan wrote to the Prime Minister that it would be an honour to chair the Inquiry. A few weeks later he agreed its terms of reference with the Home Secretary:

1. To inquire, after twelve years countering of the terrorist threat, into the reasons for security failures and the lessons to be learnt in preventing future terror attacks in the UK.

2. To inquire into present security policy and strategy towards British Islamist extremists returned and returning from conflict zones.