Everyone, at some point has failed to reach that point of departure from consciousness into sleep, because they were worrying about something, but Dr Susan Tippett says that such incidences of late-night anxiety can be stopped.

"Having a lot on your mind at 3am is not good for you," says Dr Tippett, and to prevent that from sabotaging your entire night's sleep you should make some time in the day for what she calls "constructive worrying".

"Make a list of what's bothering you and next to each thing, write down what you can do about it," she says. Often you will find that there are some things that you can do nothing about, but by simply having that fact in writing and being able to look at it provides closure on the matter.

When you find yourself worrying in bed, you can refer back to your list and immediately eliminate certain concerns as you will have already addressed them and noted down the steps you need to take.

And the rest, you will have already come to the conclusion that you can do nothing about them and know that worrying about them is futile.

Also you can say to yourself: "I have a time in the day for this, and I'm not going to think about it now," therefore leaving yourself free to try to sleep.

Dr Susan Tippett, a GP at the Nightingale surgery in Romsey, Hampshire, was talking to Sam Foster.