The historic tomb, built in 1843 by Dwarkanath Tagore, grandfather of Nobel Laureate Rabindranath Tagore, fell into disrepair before being rescued by the combined efforts of an intrepid British historian and a Singapore-based businessman. Unveiling the tomb on Rammohun Roy's 175th death anniversary, Mukherjee described him as the man who taught India "not just to accept and tolerate, but to celebrate diversity".

"It is because of him that today India sees its incredible diversity not as an obstacle to progress, but as a great asset. Modern India celebrates diversity," said Mukherjee.

The elaborate tomb was designed by William Prinsep, a merchant from Clifton, in the authentic style of a Bengali 'chattri', but its state of utter disrepair in the 1980s and 90s disappointed the many Indians who visit it every year. The restoration was financed by Aditya K. Poddar, a Singapore-based Bengali businessman, after being approached by Kolkata mayor Bikash Bhattacharya, who saw the state of the tomb in 2006.

Arnos Vale trustee and local historian Carla Contractor, who campaigned for the restoration, said: "The Rajah is rightly called the Founder of Modern India and he is still regarded as a tremendously important figure in India today. "The annual ceremony at the Rajah's tomb is always moving, but this year's event is particularly special." More than 150 people attended Sunday's ceremony - which was pan-religious in keeping with Rammohun Roy's liberal beliefs.

Restorers, working with "ancient photographs", replaced wrought iron rods holding the tomb together with stainless steel ones, carried out extensive stonework and reconstructed the joints, said Richard Smith, the chairman of the Arnos Vale Trust. "There's been quite a lot of redesigning to bring out the original features and all traces of paintwork have been removed, so that the tomb is now in its original stone finish," Smith told IANS.

"We are all quite proud of the fact that he is actually here. We do get an awful lot of visitors from India. When they come visiting England, they take the time out to come to Bristol. There's also a statue of him in the centre of Bristol city," he added.

Rammohun Roy came to Britain as ambassador for the Mughal emperor in 1831 and visited Bristol at the invitation of the Unitarian minister of Lewin's Mead Chapel. He died of meningitis on Sep 27, 1833.

Guests at the unveiling included the Lord Mayor of Bristol, members of the Unitarian Church from both Bristol and London, Brahmo Samaj members, Indian-origin councillors and other prominent representatives of the Indian community in Britain. Members of the Brahmo Samaj group performed three traditional Tagore songs.