Writing a novel is a huge adventure; when it's going well it's more fun than fun. When it stutters to a halt put it aside. Go for a swim, go for a walk, take a week off. Don't panic or be afraid; you and your characters are in it together. Trust them to come to your rescue.
Don't start writing your novel until you know your characters very, very well. What they'd do if they saw somebody shoplifting. What they were like at school. What shoes they wear. Spend days - weeks, months - being them until they thicken up and start to breathe.
The traditional writer is a sensitive only child, asthmatic, who sits on the window seat watching the drops of rain slide down the pane, very introspective. I'm not inward-looking. I would never go to a shrink. I don't want to know what I'm thinking. I don't really like discussions in my family. It may be an avoidance thing.
My perfect day is to work incredibly well in the morning and write something wonderful, then take the dog for a walk and go for a swim in the ladies' ponds on Hampstead Heath or work in my allotment. Then I get started up in the evening and go out in London to dinner or the cinema.
It's a very rich brew that's in your psyche by the time you're in your 60s, and I think that's rather interesting. It makes you feel you've lived a very long life; it's like going on holiday to three different cities rather than spending two weeks in Lisbon. You look back on the holiday, and you seem to have been away forever.