There had been an episode some months before when Gareth’s exasperation with what he saw as MI5 foot-dragging over a joint terrorist case that moved regularly between Luton and Islamabad had led him to speak frankly, as he had put it. Personally abusive and bureaucratically hostile were the words used by MI5’s head of operations when she complained to Michael. There were two case officers, one from each service, with the agent under MI5 control in Luton, MI6 in Islamabad. Normally, such arrangements worked seamlessly, with the agent unaware of any distinction, but in this case he had complained to his MI6 case officer that the handler he met when in Luton seemed unresponsive to his requests and had apparently failed to act on some very specific intelligence about the meeting of a potential bombing team in a flat above a bookmakers’. That was half true, in that the date of the meeting passed while MI5 and the police were still discussing whether to intervene; but in fact the meeting hadn’t happened and it turned out that MI5 had another source who had said it wouldn’t. The section concerned, which did not know about the joint case, had not reported the non-event to MI6, nor had news of it reached the MI5 director of operations by the time Gareth rang her to complain.

‘I confess to intemperance,’ Gareth had said to Charles with a smile, ‘and perhaps a few expletives undeleted.’

‘But what really upset them was hearing what you’d said about them to GCHQ after you’d discovered that the meeting was cancelled.’

‘Okay, take your point. Though on that occasion I was complaining not so much about this incident itself as the fact that it fitted a pattern of sluggish reporting and acting.’

‘Because, it seems, they have other sources reporting in the same area, not all saying the same thing. They have reason to be cautious.’

Gareth held up his hands. ‘Okay, okay, I shouldn’t have spoken in those terms. Point taken. Must learn to button it.’

Now, when Michael mentioned the subject again, Charles was able to take a more relaxed view. ‘Glad to hear you’ve had no more problems. He seems to have become better behaved all round.’

‘Presumably he’s aware that if he wants to succeed you he needs more friends than enemies.’

This was the first of several unprompted indications that others saw Gareth as Charles’s potential successor. Either Charles’s mind was easily read or Gareth’s record spoke for itself. ‘Could you work with him?’

The response was not immediate. ‘Yes.’

‘With reservations?’

‘Allowances rather than reservations. Allowances for temperament and manner but respect for abilities and achievements and for his reputation for making waves and getting things done.’