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Health Explained: What is a unit of alcohol?

1 November 2011 Last updated at 07:48 GMT

Do you really know how many alcohol units you are drinking on a night out? It is probably more than you think.

The Department of Health recommends that women drink no more than 14 units of alcohol a week, and men drink no more than 21.

But as our drinks get stronger and the measures larger, most people find it hard to keep track of how many units they are consuming.

Here, science reporter Rebecca Morelle visits the Science Museum's Dana Centre cafe to explain what an alcohol unit is.