The “multi million pound project” involved diverting a disused cable which originally ran between between Porthcurno, Cornwall, and Santander, Spain to connect the islands to the UK mainland.
At the same time Openreach engineers laid new fibre optic cables from the main island, St Mary’s, to Tresco and between Tresco and Bryher, and installed microwave radio links to provide the same fibre broadband services for St Agnes and St Martins.
As a result of the work islanders will be able to get speeds up to 80Mbps, ten times faster than the previous maximum.
The project is part of the £132 million Superfast Cornwall initiative being funded by the European Regional Development Fund, BT and Cornwall Council, which aims to make fibre broadband available to 95 per cent of homes and businesses in Cornwall and the Isles of Scilly by the end of 2014.
Gavin Patterson, chief executive of BT, said: “The arrival of fibre broadband on the Isles of Scilly, England’s most remote community, is a landmark event.
“It is a wonderful example of what is being achieved by BT in partnership with the public sector to bring this exciting technology to locations across the UK, which would have been considered beyond reach just a few years ago.
“Already, more than 21 million UK homes and businesses have access to fibre broadband – which puts the UK ahead of any other major European economy – and now we are pushing the boundaries to go even further.”
Councillor Amanda Martin, Chairman of the Council of the Isles of Scilly, said: “The arrival of superfast fibre optic broadband demonstrates that good partnership working can overcome significant challenges.
“Superfast broadband has the potential to revitalise the islands’ economy and to enhance the quality of living and working arrangements in the Isles of Scilly.
“I am proud that we are now one of the best connected archipelagos in the world. This would not have been possible without the significant investment by BT and the European Convergence programme.”