When I get to Brussels I know I’m being watched - and I know who’s doing the watching. At first, I’ve a good mind to get right back on the next Eurostar back to Waterloo. Then I think, ‘What the hell, it’s all set up!’ Spavin's no threat; not to me, anyway. All the same, I take one of my pills.’

I walk into the Connaught, near the Bourse. Spavin's climbed out of the taxi behind mine and rushes over to have a word with the driver who’s just dropped me.

I spotted him on the train as we left Lille, hiding behind a free copy of The Times. That’s typical of him, blowing his cover when the suspect has to take a leak. He can’t have told his boss; Collins knows better than to send an amateur like Spavin to catch me out.

I like the Connaught. It looks like something out of Poirot, with that wood panelling and fan-shaped wall lights, but nobody’s going to remember you. Well, they won’t remember me, anyway; bloke in his sixties wearing stuff that could be picked up in any branch of M&S. I'm just a summer tourists in Brussels; widower, somebody’s granddad enjoying a cheap Euro break.

As soon as I leave the Connaught, they’ll search my room.

‘Arguably the most beautiful city square in Europe’ says the guidebook. They won’t get any argument from me. I’ve seen a few places since my son Mark suggested I join him on the day trips, so I ‘m quite an expert. His wife said that ‘the children should know something of their history.’ Privately, I thought it would be all a bit one-sided, but I said nothing.

The kiddies preferred those ruined castles where they could pretend to be knights on horseback, but myself, I soon began to see the possibilities in the stately homes. They were stuffed with what the afternoon TV programmes call ‘collectables’.

Not that I didn’t sympathise with Mark about the cost of raising kids these days. It was different for me when he was a nipper – the market barrow, with a bit of no-questions business on the side, and if I had to be away now and again, it didn’t matter too much.

It’s for the kiddies’ sake I decided to do one last drop. Mark gave me a lot of ear-ache until in the end I had to pretend I was only joking. Spavin was wrong when he said Mark was a chip off the old block – he hasn’t got the bottle, for one thing, and for another he has those two nippers to think about.

I go for it straight away when my old contact Frank suggests Belgium to fence the goods. ‘Your dad’s sweeping the Jerries out of Belgium’, my mum used to tell me. I didn’t know what she meant, but I remembered the name. He didn’t come back with any medals.

I sit in the Grand Place, and look at the buildings with their pointed fronts sprouting statues, and the big umbrellas over the tables, the beer all different colours, in big wine glasses.I could get used to this. Frankie says he can get a million from a collector in Amsterdam.

Spavin is watching me somewhere, drinking lemonade. I could almost feel sorry for him. I saw him earlier, chatting up the hotel receptionist, who didn't look too impressed.

I pretend to look at the guidebook before I catch the 48 tram, starting off underground and ending up in some cobbled suburb. I get off near to the street, Rue de La Perche, carved on my brain since Frankie suggested it as the venue for the drop. I know the name of the place: Swimbad Victor Boisin. I see it more or less straightaway, and don’t give any sign that I know Spavin is behind.

It’s touch and go whether he gets on the back of the tram, but I just step back in time to catch sight of his ginger bonce before he disappears into the crowd in the other carriage. I have a very uneasy ride for a minute or two, because there’s a lot of pickpockets on trams. Then a little kid gives me his seat.

The Schwimbad is really old. In fact, it’s so old I think it probably has some kind of preservation order on it. The guide book says it’s Art Deco, and I know just enough to see that from the decorations in the café bar. The baths doesn’t even have separate changing rooms, only these numbered cubicles all round the edge of the pool. You go to an empty one, and when you’ve changed into your swimming things the door shuts automatically behind you with your belongings left inside. You have to remember the number, and after your swim you get an attendant to open it again.

I’m thinking it’s about now that Spavin will be trying to hire a costume from the surly bloke on the front desk. They're not exactly hostile, the Belgies, and they speak English, but not what you’d call helpful, either. I spot Frankie at the other side of the café-bar, where the windows look out over the pool.

I freeze, wondering what to do. If Spavin sees me talking and recognises him, we’re done for. I look at him and flip my head sideways. Frankie, he’s as good as gold and catches on right away. He scribbles numbers on the back of a cigarette packet and holds it up for me to see. Then, putting down his glass, he slips off towards the gents.

Soon I’m in the pool, watching Spavin argue with one of the lifeguards. He’s probably trying to find out which of the cubicles I used to change into my togs, and where I might have left the item. It’s number 24, but the lads say they didn’t notice. Frankie must have made it worth their while. So he picks himself an empty cubicle, goes in and is soon out again, wearing goggles and a swimming cap, with a pair of trunks flapping against his scrawny legs.

There's not many people in the pool and in no time I’m swimming lengths. Spavin is shivering in the shallow end. He knows he’ll have to wait to see which cubicle I’ll go to and change back into my clothes. What he doesn’t know is that Frankie has left me, in 31, a set of identical clothes to the one I was wearing plus a towel and enough money to get me back to the Marriott. All he has to do is wait until Spavin has gone, empty-handed, and then pick up the goods from 24. It seems fool-proof.

I didn’t ask Frankie why anyone would part with a million for Wellington’s Star of the Garter medal. You wouldn’t believe the amount of stuff lying around on public display up and down England – the real thing, too, not even replicas. You just have to know where to go to find it. A contact who knows a thing or two about CCTV cameras and security case alarms comes in handy, as well.

It’s when I’ve stopped for a breather at the deep end that it all starts to go pear-shaped. Two Belgian coppers appear, on the side at the shallow end, yelling at me to get out. I’m cursing Spavin, who must somehow have managed to call in some local back-up. I’m panicking, too, in case they hold me while they search the cubicles. The coppers start running up and down, one of them blowing a whistle. I make for the shallow end as slow as I can, thinking about what I’m going to say.

It’s only when I’ve nearly there I suddenly realise it’s not me they’re shouting a; it’s Spavin. He’s going mad as they haul him out, waving his skinny arms and squawking, but they don’t take any notice - uniform branch probably don’t speak English – and they soon have the cuffs on him when he won’t come quietly.

But it’s not over yet. I’m about to get out when an iron band clamps round my chest, and I can’t move. I have to rest against the side, breathing slowly, like the doctor said, until the pain stops.

Later, on the tram back to the Bourse I’m feeling a lot better. I think of Spavin hauled up before Collins. He’s been arrested for indecent assault while travelling on a public vehicle.

According to one of the lads on the poolside, that was the charge when the Belgian uniforms got him. It seems Spavin had been crushed up against a young woman in the tram and couldn’t keep his hands to himself. When he got off she called the police on her mobile and told them Spavin had gone into the baths.

Back in the sunshine in the Grand Place I take the call from Frankie to confirm he’s collected the medal. I’m browsing through the National Trust Handbook, or Collector's Guide as I've come to think of it, wondering if I should specialise in Art Deco, maybe make things easy by taking the kids to Eltham Palace, or visit Churchill’s place down in Kent. I bet there’s a few medals hanging about doing nothing.

It’s then I notice the black shiny shoes, right in front of me. And somebody’s saying my name.

As I find out later, they connected me with the Apsley House job because I was caught on the CTTV cameras as I left. I was more concerned at the time that Mark and the kids might have spotted something. Then they tie me in with the train booking to Brussels.

So that’s why I’m sitting here talking to you and waiting to see my brief, instead of sizing up Chartwell. Frankie’ll see Mark right after he lies low for a while, so I'm not too worried. As for me, my brief says it could go either way: true, I’ve got form, but the judge might give me a suspended, on account of my age and health. Wish my old dad could be here, though. He'd see the funny side.