TONY BLAIR was last night resisting growing calls to rule out a General Election in May as the foot-and-mouth crisis worsened.

Ministers also announced plans to launch a "pre-emptive strike" against the disease, culling up to 100,000 animals which may have come into contact with infected livestock.

The news came as the Ministry of Agriculture Fisheries and Food (Maff) confirmed another 26 cases in the UK, including two new outbreaks in County Durham and four in Cumbria.

In County Durham, Maff vets moved into High West House Farm, Tow Law, and Hill House Farm, Witton-le-Wear.

By last night, 231 outbreaks had been confirmed in the UK. The new sites included a farm in Cheshire, a county which was previously disease-free.

The sheer scale of the epidemic, and the restrictions placed on movement, particularly in the countryside, has led to mounting pressure on the Prime Minister to postpone council elections set for May 3 - the same date that is widely believed to have been pencilled in for the General Election.

Voters will be going to the polls up and down the country to elect their local councillors, many of them in rural shires.

But a number of authorities, including North Yorkshire, are expressing concern and want the date put back to later in the year.

It will take an Act of Parliament to affect such a change but the issue is expected to be high on the agenda when the executive committee of the shire counties' County Council Network meets tomorrow in London.

David Ashton, leader of Tory-controlled North Yorkshire County Council, said yesterday: "The last thing we want is an election as we try to cope with foot-and-mouth disease, and all its implications for our tourism industry.

"We are also still trying to recover from November's floods and it is only a fortnight since the Selby railway disaster.

"I don't think people in North Yorkshire see an election as being the something they need to have at the moment."

But Environment Minister Michael Meacher emphasised last night that the Government had no intention of postponing the local elections.

'There's really no justification at this point for postponing or cancelling those elections," he said.

"Obviously we have to look at the course of the outbreak, and if it did dramatically worsen, obviously we would have to take account of that.

"But at this stage, there is no justification for cancelling and there is no intention to do that. There are no contingency plans, and we do intend to go ahead."

In another development last night, officials admitted they were powerless to stop a caravan company reopening a site only fields away from a diseased farm in County Durham.

Following a two-week delay to the start of the season because of the foot-and-mouth, the Oakleaf static caravan park on the banks of the River Wear at Wolsingham, in Weardale, County Durham, will open its gates tomorrow.

Twenty families from around the region have caravans on the site.

Mark Robson, of owners Robsons of Wolsingham, said: "Our site is not on farmland and all the roads around here are open. We have transport running in all directions in this part of the dale. At the end of the day, I have a business to run."

A spokesman for Maff said yesterday it was "up to organisers and people to act responsibly".

Durham County Council said it could only take action if the public ignored closure signs barring the way to footpaths, picnic areas and parks.

The outbreak is costing tourism up to £250m a week.

But Agriculture Minister Nick Brown denied accusations that the Government had mishandled the crisis.

He said there was "an emerging possibility" that some restrictions could be lifted in areas which were free of the virus.

Tony Blair said the possibility of stepping up the slaughter in those areas most directly affected was being considered.

He said: "It is entirely right that we look to see how we can take more urgent measures in those areas.