But, with the number of cases now at 1,341, ministers remain cautious about whether a programme of immunisation would be the best course of action.

Agriculture Minister Nick Brown has said no decision will be taken until farmers have been consulted about vaccinating animals unaffected by the virus.

Many farmers are concerned vaccination is of limited effectiveness and would delay the return of Britain's "disease-free" status, necessary before meat and milk exports can be resumed.

Shadow Agriculture Minister Tim Yeo MP said: "The longer the government dithers over vaccination, the more their failure to control foot-and-mouth disease is exposed.

"Having failed to carry out the slaughter policy effectively, ministers must now make clear without delay what the scientists recommend on vaccination."

"We will support new measures to control foot-and-mouth disease provided they are based upon sound science."

Export status

Prof King told BBC News 24 vaccination was not an alternative to the mass cull.

He said the programme was not likely to have any effect on the length of time it takes for Britain to regain its disease-free export status.

NFU president Ben Gill told BBC Radio 4's Today programme that leading experts still thought vaccination was not the answer and said he was still waiting for the government's response to 50 questions needed to assuage farmers' doubts.

The army has said it already has half a million doses of vaccine and has the resources to support vaccination if that path is chosen.