Three new cases of swine flu have been confirmed in Britain, bringing the total number to eight, the Department of Health announced on Thursday.

Two of the cases are in London and one in Newcastle, where two students who shared a house with the patient are now being treated with an anti-viral drug. The unidentified person recently returned from a trip to Mexico.

The condition of the latest three cases is not known. So far five of the British flu cases, which includes a girl of 12, have responded well to treatment.

Earlier, the government's chief medical adviser warned that Britain will see "many, many more cases" of swine flu.

Health Secretary Alan Johnson said British health authorities were doing all they could to contain the virus, but were making preparations in case it spread.

So far the cases of swine flu had been directly associated with Mexico, rather than spreading within Britain, he added.