Britons warned off India

It also advised any British nationals currently in either of the two countries to consider leaving, because of the "increased risk of conflict".

Visitors to India were warned of the risk of terrorist attack, particularly in the vicinity of key government installations.

India and Pakistan have been at loggerheads for some time over the disputed mountainous region of Kashmir, but officials have become alarmed by recent increased troop movements.

Announcing the new advice, Foreign Secretary Jack Straw said he did not regard war between the two nuclear powers as inevitable.

However, he said he had a clear "duty of care" for UK citizens, including staff in diplomatic posts.

The Foreign Office has been advising against all non-essential travel to Pakistan since 11 September, and reduced its diplomatic staff on 22 May.

However, this is the first time tourists have been told to avoid India as a whole, rather than just the troubled state of Jammu and Kashmir.

Refunds

Driver Singh, from Bradford, has just cancelled a family holiday to India which took three years to plan.

He said: "In the past there has been gunfire across the borders, but this time, with missile testing and with the area that I'm going to in India being close to the border, it's much too much of a risk."

There is a large Indian and Pakistani population in Bradford and there are fears the conflict over Kashmir could create problems within the community, said the BBC's north of England correspondent John Thorne.

Accountant Rajeev Dewedi, whose family are staying with him on a three-month holiday from Delhi, said it was difficult to ignore what was going on in India.

He said: "We don't really like to import politics from back home, but at the same time, we are concerned about the people, like our families are back home, and we want peace there just the way it is here."

Sean Tipton from the Association of British Travel Agents (ABTA) told BBC News Online holidaymakers who had arranged a trip to India should contact their travel agent.

Package holidaymakers would be offered a comparable alternative such as Thailand or a full refund, he said.

Independent travellers would be offered an alternative flight or a full refund, or the option of a flight at a later date assuming the situation improves.

No disappointed travellers would be offered compensation, he said, as the circumstances were completely beyond the travel companies' control.

Tour operators already in India would pull their clients out at the first possible moment, he added.

20,000 Britons

However, some tourists such as trekkers were in quite remote areas and it could take some time to reach them.

The Foreign Office said the move would be publicised within India, but that friends or relatives of tourists backpacking in the region might want to let them know by usual channels such as e-mail.

The Foreign Office said any UK national in either of the two countries should contact travel operators about flying out immediately.

It said it was in touch with the commercial airlines, which were continuing to operate as normal for the time being.

The Foreign Office estimates there are about 20,000 British nationals living in India, not all of them registered with consular officials. About 700 Britons are registered in Pakistan.

The families of UK Government staff in north India and those staff not engaged in essential work were being offered the opportunity to come home immediately at public expense.

The Indian visa service would continue but at a reduced level, Mr Straw said.