There’s good news for tea loving office workers who rely on their cuppas to keep them going.

Drinking four to six mugs of tea a day is as good for keeping yourself hydrated as a litre of water, a study has found.

The finding disproves the idea that regular tea drinking can dehydrate the body because of its caffeine content.

The research also found no negative health effects from drinking that amount of tea.

In the UK clinical trial 21 volunteers drank either four 240ml mugs of tea over a 12-hour period – equivalent to just under one litre of tea in total – or a similar amount of plain, boiled water served warm.

The tea included 20ml of semi-skimmed milk but no sugar.

The test was also repeated using six cups of tea or plain water, equivalent to nearly 1.5 litres of fluid, to investigate the effect of intakes.

Tea or water and a controlled diet were given on separate test days. There was a ban on vigorous exercise, other caffeinated products and alcohol.

Blood samples were taken before consumption and at regular intervals to check hydration levels. Analysis found no significant differences between drinking tea and water.

The study, commissioned by the industry-backed Tea Advisory Panel, is published in the British Journal of Nutrition.

Dr Carrie Ruxton, nutritional advisor to the panel, said: 'Tea is an excellent way to maintain healthy fluid levels. In addition, tea is a rich source of flavonoids, which have been associated with a reduced risk of heart disease and stroke.'