Paul McCartney sails to Santa Catalina Island, California

On 21 June 1968, Paul McCartney had arrived in Los Angeles with other representatives of Apple Records to promote their label to Capitol Records executives. On this day, however, they had a day off, allowing McCartney to spend time with his new girlfriend Linda Eastman.

In addition to McCartney, the Apple party included label boss Ron Kass and employee Tony Bramwell, as well as McCartney's childhood friend Ivan Vaughan. On this day they were invited to sail on a yacht belonging to Warner Bros executive John Calley.

Paul knew that if Linda went with him on the boat, the news [of their relationship] would get out very quickly. He was torn between going, or keeping her a secret for a little longer by hiding her back in the bungalow. In the end he decided they would both go, and Linda could always say she was just taking pictures.

As we left the hotel to get into the limo, [actress] Peggy Lipton suddenly appeared, bikini and towel packed in her beach bag, ready to spend the day with us. Somebody must have told her we were going sailing. 'Oh my God,' said Paul when he spotted her. 'She can't come.'

I had to tell her in the nicest possible way that it was a private party, while Linda stood quietly to one side pretending she wasn't with us. Peggy was very upset and got very argumentative. I realised that she needed the publicity for her career and had been told to make sure she got it, but Paul was tired of girls who used him. We drove off fast, leaving Peggy standing on the hotel steps in tears.

It was one of those perfect days, though not for Peggy, of course. We sailed to Catalina, feeling like Bogart and Bacall for whom the island was a favourite destination, along with the Flynns and the Fairbanks. We dived off the sides of the sailboat into the clear blue sea where dolphins swam, sunbathed on the decks, ate bacon sandwiches and drank champagne. It was a wonderful day, an antidote to the months of madness in London.

Some brief colour footage of Paul and Linda exists from this time, on the boat and around the pool at the Beverly Hills Hotel. It was shot using a home film camera, and lasts little over 30 seconds.

This was the final day of the Apple promotional trip. In the evening the party flew from Los Angeles to New York, where they caught a connecting flight to London.

Late that afternoon, we checked out of the hotel to return to London. Paul and Linda were like Siamese twins, holding hands and gazing into each other's eyes all the way to the airport. In the VIP lounge, they sat apart from us on a small group of seats in a central aisle, the kind of seats that are back to back with another row. Suddenly, the doors burst open, like the sheriff and his men at the big bad saloon.

'FBI!' one of them barked, flashing a badge. 'There's a bomb warning on your flight. Do you know of any Caucasian male with a grudge against you?'

Paul looked surprised. This was years before stars were assassinated and needed bodyguards. He said, 'No, nobody.'

'Do you mind if we search your baggage?' they asked.

Out of the corner of my eye, I noticed Linda very swiftly aiming a neat little backward kick with her heel. Her square vanity case, which she had placed on the floor beneath her seat, skidded to the row of empty seats and, fortunately, came to rest exactly underneath one of them. Casually, she stood up. 'Well, guys, I guess this is good-bye,' Linda said. 'I'd better check on my flight.'

'What flight are you on?' one of the agents asked.

'New York,' Linda said. I'm not traveling in Mr McCartney's party.' She smiled at us all and sauntered off through the door of the VIP lounge as if she had all the time in the world, and as if there wasn't enough marijuana packed into her vanity case to get a herd of elephants stoned.

We all wondered if Linda had managed to sneak back for her vanity case, or if it remained there. Who knows? I never asked.