Last week was a nightmare for former MI6 officer Christopher Steele. With his long experience in Moscow working undercover against the SVR and FSB, Steele is a professional in the covert world. But now that he has been outed as the writer of the Donald Trump memo, with its scandalous claims, he has suddenly become one of the most-wanted people in the world. To a man like Steele there is only one option: hide, go on the run. But that's not as easy as it sounds, even for the experienced spook.
So what to do?
The first question he will have asked himself is this: how much time do I have? How much time before the anonymous black Mercedes with the three fit young men in it starts cruising noiselessly down the street? Or, worse, how long before the blues and twos and Mr Plod arrives, demanding embarrassing answers, plus the press pack?
Second question: What's my aim? A permanent disappearance, or can I just hide out till the fuss blows over?
This is what really demands clear thinking, just like they taught you at the Fort, or those scary intelligence officer's new entry course training exercises in seaside towns, pretending to be on the run with the Security Service, the Intelligence Corps and the local police hunting you down. But this time it's for real.
Think! Is this short term or for as long as it takes? Do you need a new identity to be truly safe? Perhaps most important of all, will my old mates at the Secret Intelligence Service (SIS, better known as MI6) help? Or am I on my own, suddenly a pariah of the Western and Russian intelligence community? Who can I trust?
If you're just on the run until it's safe to stick your nose out, the rules are different. Find friends you can trust, or find a safe bolthole and lie low. Think Lord Lucan.
If it's a long-term bug out, though, some other basic rules apply. First, get the hell out of the house - now! Next: it's cash only from now on, at least for the short term. No credit cards. No electronic trail. Get the biggest slab of money you can and move. Money's anonymous. That's precisely why governments hate it so much.
Next, get rid of that mobile. OK, it's your indispensable lifeline to work, friends, family, even your mistress in that secret app. But ditch it!
Remember: Transmission is treason. You can always get your hands on a cheap pay-as-you-go mobile, if that is important. Or use a call box - when you can find one.
Then it's time to grab that extra passport, acquired along the way in your work for British Intelligence. If you've had any nous, you've got more than one and some associated plastic too for when things quieten down. The Narodny Bank of Moscow has most money and there's more in Zurich.
The next move for the long-term runner? Blindingly obvious: get out of Britain as soon as you can. How? Forget airports and ferries. Far too dangerous. Go fishing for mackerel instead. Hire a fishing boat at Deal, Kent, for £500 and get dropped off on the Belgian coast on a rising tide at dawn, no questions asked. Once ashore and heading for Brussels (you have bought tickets to three different places, haven't you?) resist the temptation to contact your friends and family. Instead, take stock, hole up for a while.
Eventually, contact that mate you know in the press and plead your innocence. Tell the real story. Good luck. GCHQ will be on to you in a heartbeat. So will the reptiles.
So it's time to move - again. Now you have to wait. Just hope you don't get sick and have to go to hospital. And hope the cats are being fed. But once that first panic of flight has worn off, some serious soul-searching is required. Who will be hunting the fleeing spook? And, more important, why?
If it's just the media, no problem, he can wait that out. They'll soon move their resources to the next story. But if it's Western intelligence, then hiding on the Costa del Sol won't work for long. Has he committed any criminal offences? Will the Feds drag him back to the States to testify?
Legally, can they? The doubts crowd in. If it's the vengeful Russians, then the stakes are higher. Much higher. Polonium-210 in a cup of Tetley isn't a nice way to go. Where to run? Where to hide?
The spook on the run will be looking for a long-term hiding place, as well as weighing the chances of talking his way out of trouble. The niceties of extradition won't stop the Kremlin. So the pressures - security, financial, personal - plus the dangers will cause sleepless nights.
Thankfully, there are still a few places, even some quite comfortable places, with a sea view, where rules are not quite set in stone. Somewhere, perhaps, like unrecognised Turkish North Cyprus. Get there, get settled, then start to call in all those favours owed in more than 20 years of spying for your country.
Because you will want to get it straightened out eventually. Otherwise, there's always the danger that, one day, you look out of the window to see that anonymous black Mercedes with the three fit young men getting out...
John Hughes-Wilson spent 25 years in British military intelligence and special forces.