The FO is understood to have approached the High Commissions in both countries asking when a suitable time for the visit might be. Diplomats are believed to have advised the Prime Minister's staff that the earliest possible time would be around New Year.
Any visit would be deeply controversial. Last year, during the Queen's visit to the sub-continent, Robin Cook, the Foreign Secretary, caused a political storm when it was suggested he had offered to mediate over the Kashmir dispute.
Kashmir is India's only Muslim majority state and has been the cause of tension between the two countries since Partition in 1947.
India currently holds two thirds of the Himalayan state and is adamantly opposed to any mediation and, according to analysts, keen to maintain the status quo. Pakistan, though, would welcome outside intervention.
For six days the two nations have been waging a fierce artillery duel along the "line of control" which splits Kashmir into Pakistan-held and Indian-held zones, although yesterday the firing appeared to have slackened.
The two countries have gone to war twice over the former kingdom. There are fears that the dispute could provoke a third, possibly nuclear, conflict.
In the most recent firing more than 90 people, mainly civilians, have been killed and hundreds more injured. Sustained firing by both Indian and Pakistani heavy artillery and mortars at both civilian and military targets has forced thousands of villagers on both sides of the border to flee their homes. Last night they remained in make-shift accommodation waiting to return to their homes.
Mr Blair is known to want to reduce tensions between the two nations, although it is unclear whether any visit would involve diplomatic initiatives. Even the most uncontroversial visit to south Asia would be extremely well received by the large Indian and Pakistani communities in the UK.
However, earlier this week Foreign Office minister Derek Fatchett went out of his way to call on Indian and Pakistani leaders to enter into dialogue, and Mr Blair is, according to diplomatic sources, keen to kick start talks.
The sources revealed that in the immediate aftermath of nuclear tests by both India and Pakistan Mr Blair telephonedthe leaders of both countries to urge them into dialogue, particularly over Kashmir.
"Britain would almost certainly be first choice for the Pakistanis in any mediation," one diplomatic source said. "Not least because we were involved in the whole mess at the start."
He added that any visit, however, would be impossible for several months. "With the nuclear tests, anything in the next three months is politically impossible and it takes at least three months to set up a tour like that."
A spokesman for the British High Commission in Islamabad said he was unaware of any plans for a visit. Contact by telephone or letter would be more likely, he said.
Nawaz Sharif, the prime minister of Pakistan, and Atal Vajpayee, the Indian prime minister, met for the first time since the nuclear tests at the annual conference of the South Asian Association for Regional Co- operation (SAARC) in Sri Lanka last month.
The dialogue between the two leaders was unconstructive, however, and the talks collapsed acrimoniously. The Indians said that the Pakistani government was being `neurotic' about Kashmir, although last night Vajpayee told parliament that he was interested in talking about peace.
Earlier this week the Indian newspapers said that the recent border clashes had been provoked to keep the issue alive in the minds of the international community.
Politicians in Islamabad have a genuine, and often voiced, fear that Vajpayee's newly elected Hindu nationalist government is committed to taking Pakistan-held territory by force and regularly accuse Delhi of deliberately raising tensions.
There have been regular clashes throughout the summer along the border between the two countries although the recent fighting is the most intense.
The artillery duels are often started by the Indians following attacks on their security forces by separatist guerrillas.
The guerrillas, trained by extremist Islamic groups in Pakistan with the tacit support of the government, regularly cross the border to attack Indian troops and, the Indians allege, Hindu civilians.
Yesterday Indian authorities claimed that the militants were responsible for two further attacks. Eighteen people were killed in a village in Poonch district and seven wounded in a grenade attack in central Srinagar.
The groups, members of which were responsible for kidnapping Western hostages several years ago, are often recruited from experienced fighters who have fought in Algeria and Afghanistan.
Pakistani authorities deny their involvement in what the Indians call "warfare by proxy" and claim that Indian commandos regularly cross into their territory to plant bombs and attack civilians.Reuse content