The so-called 'Million March' planned from Trafalgar Square to Downing Street on October 26 is being led by Barrister Sultan Mahmood Chaudhry.
While his group claims overwhelming support from various communities, others have dismissed it as against the "national interest of the people of Jammu and Kashmir".
India has raised with Britain its concerns about the planned rally here.
The matter was taken up by External Affairs Minister Sushma Swaraj during her talks with Britain's Deputy Prime Minister Nick Clegg in London last week.
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Dr Shabir Choudhry, spokesperson for the Kashmir National Party and director of the Institute of Kashmir Affairs, said "They are spending huge amounts of money to try and get people to attend. I had a phone call from an old friend in Halifax (west Yorkshire, England) who said that after the Friday prayer it was announced that free coaches and free food will be provided for volunteers who attend the march."
The date of the march, October 26, has also been highlighted as significant for pro-Pakistan groups as it was on this date in 1947 that the last ruler of the state of Jammu and Kashmir acceded to India.
The organisers stressed that the "peaceful march" is intended as a protest against the "atrocities in the region".
"It is not anti or pro any country. It is simply about people in Britain raising their voice against injustice," said Majid Chaudhry, the organiser of the 'Million March'.