water with lemon juice in the morning, then take a 1litre bottle with you, either at home or on your desk at work, and sip it gradually during the day. As soon as you feel able, switch to a 1.5-litre bottle. Obviously don' t force more down than you can manage. Also make sure you are supporting your liver and kidneys with other measures - that is, a stimulant and alcohol-free diet with plenty of nutrient-rich vegetables and fruit.

Rather than forcing yourself to drink a specific amount, I' d be guided by your own body. Any combination of the symptoms below could be a cry for water, and recognising them can help you become more in tune with that.

Are you prone to constipation?

Are you often thirsty?

Do you have joint problems?

Do you feel tired?

Are you having difficulty concentrating?

Are you overheating?

Do you have dry skin, mouth or lips?

Do you get frequent infections?

Do you have dry, brittle hair?

The other way to judge is by the colour of your urine. If your urine is a very strong, dark yellow, you' re not drinking enough. This simple gauge is, however, complicated by the fact that riboflavin (vitamin B2) makes the urine a fluorescent kind of yellow. Ideally, your urine should be a light straw colour. If, however, it is often clear, like water, you may be drinking too much water and not taking in enough nutrients.