Every two-year-old in Britain could be given a flu jab under plans being drawn up by health officials, The Independent on Sunday has learnt.

But mass pre-school vaccination will get the go-ahead only if it protects enough adults from the virus to cover the cost of the jabs to the NHS.

The capacity of young children to spread flu, well known to parents, makes them a priority for vaccination, according to some public health experts. One of the Government's advisers said immunising children against the virus could also help to shore up defences against bird flu.

However, vaccination pressure groups voiced alarm at the proposals, insisting that young children should not be "used for the benefit of everyone else".

Some studies suggest that if four-fifths of children aged between six months and 18 years were given jabs, the general incidence of flu could be reduced by more than 90 per cent. Infants are already routinely vaccinated against flu in the US.

At present in the UK, only young children at particular risk are given a flu jab. Under proposals revealed in the minutes of the Government's expert panel on immunisation, healthy children aged from 23 months to six years could be given two doses of vaccine.