Aweek or so later we docked at Liverpool and Peter Lupino was there to meet us. What a help he had been to us and was still to be. He took me to lunch and then back to Derby House for a council of war. What a blessing it was that he knew show business. His first question: ‘What have we got left, Pat?’

‘Only the climax of the picture, Peter, that's all.’

‘Involving what exactly?’ Pencil in hand, at his desk, surrounded by pneumatic tubes, occasionally spewing messages into their wire baskets. He ignored them, a sixth sense suggesting that they were unimportant. He had more important business on hand. I started to enumerate what remained to be done. ‘We have to sink the U-Boat. To do that convincingly we have to have the Leander's gun barrel firing at it in foreground.’

‘Any gun barrel will do?’

‘Yes. The first shot goes over so we must see the splash beyond the U-Boat, the second short and the third a direct hit.’

‘You've done all the action leading up to the gun firing?’

‘Yes. Then there's the cat-and-mouse game. Griff and Rogers watching the periscope circling as they make for the gun aft.’

‘That means a submarine and the Patricia again, if she'll play. Her gun'll do, one barrel's like another.’

‘Sadly we couldn't get the shots of Leander with her lifeboats in foreground as seen by the U-Boat.’

‘Oh Gawd.’

‘I know; wasn't through want of trying. Both Vinten motors burnt out through constant camera jamming due to faulty stock: strain on the motors was too much.’

‘Those may be more difficult to lay on than the mock battle. Means sending out a special escort to meet her. Pray God she'll still be with us. She'll have to be detached from the convoy … My sainted aunt, rather organise the Spithead review. Anyway, let's go for mock battle first.’

We had had hardly time to unpack, get our bearings and see the rushes when news came through that Peter had arranged for a submarine and the Patricia, which had helped us in the rescue scenes of the lifeboat survivors, would be at our disposal at Holyhead for a day on 7 September.