For a while this week, I had to cope with the discovery that my sister Bobo might be the main man on the Isle of Wight. Miss Debbie Mason and I were driving in that direction when she suddenly did a U-turn and headed back to London.

"What's up?" I said.

"I'm not going into the jungle with you," she said. "You're not streetwise."

My heart sank. If Miss Mason had joined the ranks of the streetwise, we would be disconnected from the national grid by tea time and our goods would be distrained by a Pakistani beadle.

Nor could we hope for Isabelle to put us up. Isabelle, having discovered her brother was in a jam in Bogota, and in a reverse play intelligible, perhaps, only to the streetwise, posted him an ounce of Colombian pink. Her case comes up on Tuesday.

"We're not going into the jungle," I said. "Merely to the Isle of Wight. Fat landladies playing bowls, low-grade regattas, failed tradesmen turning turtle."

Miss Mason said I knew nothing about shooting docu-dramas, so I gave her a short burst on the subject of grandmothers and eggs and so forth, but, not wishing to be wordy, resisted the temptation to point out that the Italian episode of Root Into Europe might have been better had we not been obliged to slip the local capo di tutti capi half a monkey and, further, to cast a scene in an elegant Roman cafe entirely from among his louche-looking nieces and barrel-shaped bodyguards.

"A couple of years ago," she said, "I'm in Kenya filming a docudrama. We're driving into the jungle when we notice we're being tailed by a full tribe of Masai warriors, jumping up and down and waving their spears.

"Being dickhead English, and taking them to be tourist Masai laid on by the government for picturesque purposes, we think, how quaint, and we wave at them in a dickhead English way and drive deeper into the jungle.

"Next thing we know, we're surrounded by 300 bollock- naked Masai warriors doing a war-dance and we think, hello, this isn't very nice.

"Then the chief arrives, seven feet tall and wearing a suit and Rolex watch and speaking perfect English. He probably went to effing Winchester, I mean. They probably send one of them to Winchester to take care of dickhead English film-makers.

" `What are you doing?' the chief says. `Filming,' I say. `This is my land,' he says. I'm thunderstruck. `But I've got a government permit,' I say, and I show it to him. He only tears it up and throws it on the ground! Then he points to his wrist. Shit, I think, I've got to get him another Rolex watch as well. `A gift from the producer of Out of Africa,' he says.

"I get the picture at last. `Is there a bank near here?' I say. Really! We're deep in the jungle, using a bucket behind a bush, and I ask him if there's a handy branch of Barclays. I end up driving to Nairobi, where I get him his 21,000 Kenya shillings. So please, don't tell me about filming docudramas."

I put forward one more argument in favour of myself, pointing out that I, too, went to Winchester and that if some Masai warrior on the Isle of Wight tried to come the executive producer with me, I'd clamp him in a notion.

"What's a notion?" Miss Mason said.

"Winchester's private language," I said. `` `On your bogle, sunshine,' I'll say, `or I'll mons you in Gunnars Hole.' "

"We'll not have any of that, thank you very much," Miss Mason said. "Not on a shoot of mine. We'll pick up Frankie Fraser and lovely Marilyn. They'll look after us."

Frank was about to do a national tour to promote the paperback edition of his excellent memoirs, Mad Frank (Little, Brown & Co) - at literary lunches, sharing the podium with Lady Antonia Pinter and such like - but he goes the last yard for his pals, does Frank, so he cancelled the tour and the four of us set off again for the Isle of Wight.

Then I had an inspiration. "My sister Bobo's land marches with Beaulieu's," I said. "We'll drop in for tea. She'll tell us who to straighten on the Isle of Wight."

Bobo was pleased to see us, and I have to say that Frank and my brother- in-law Christopher, both having been only to minor public schools (Radley and Wellington, respectively), seemed to be more comfortable with each other than they were with me - or would be indeed with the Masai warrior who went to Winchester and who, according to Miss Mason, owned the Isle of Wight. Then Bobo asked us what our business was.

"We're making a film," Miss Mason said.

"Naff things the Welsh do," said Frank. "Display pride in the shirt, sledge in the scrum, find themselves confounded by an English prop (`Really, boyo? I haven't bonked yours, but I'm the only lad on the park who hasn't), tie leeks to the goalposts ... "

"We're not filming in Wales," Miss Mason said.

"I know that," said Frank. "But the Isle of Wight isn't playing England on Saturday. I'm trying to keep this column topical."

"That will be 88 Hampshire shillings," Bobo said.

"Tell her, Frank," I said.

"A word in your ear, Button," Frank said. "She's a formidable woman, your sister Bobo. I think we'd better pay."

"Are you the main man?" I said to my sister Bobo.

"No," she said. "That was for the tea. The main man's old Lady Huggins, who lives next door."

Frank went next door and returned in minutes, looking a little shaken. "21,000 Hampshire shillings," he said.

"You paid? You've never backed down in your life!"

"I hadn't previously met Lady Huggins," he said. "She's worse than your sister Bobo."

"I told you," Miss Mason said.