Northern Ireland and Scotland should be linked by a tunnel, which would allow the traveller to go all the way from Cork to South Korea by train, according to a leading authority on public finance.

David Clement, a past chairman of the Chartered Institute of Public Finance and Accountancy (CIPFA) in Northern Ireland, said such a tunnel would be the next logical step following the reopening of St Pancras Station in London, bringing faster travel from Britain to the continent.

He will be presenting his arguments for a physical link across the North Channel when he appears at the CIPFA Transport and the Environment event on Tuesday in Belfast.

He will tell delegates that a tunnel would benefit the economy of both countries, and would allow travel from the south-west of Ireland right the way through to South Korea solely by train.

Mr Clement said yesterday: "The idea of a tunnel between Northern Ireland and Scotland is extremely exciting. Based on recent research conducted by the Centre for Cross Border Studies, there is enormous potential benefit for the Irish economy, north and south.

"I really hope that the new Northern Ireland Executive will pursue this exciting scheme."

Mr Clement will be part of a panel on Tuesday discussing what needs to be done to balance the need for an effective transport system with the need to protect the environment.

The Centre for Cross Border Studies was founded in September 1999 and is based in Armagh and Dublin.

It researches and develops co-operation across the Irish border in areas such as education, training, health, business, public administration, communications, agriculture and the environment.

In August, the centre's director, Andy Pollak, first floated the idea of a 21-mile bridge or tunnel connecting Scotland with Ireland. He thought a figure of £2bn or £3bn might be needed for a fixed link between the countries.

"The arguments against such a hugely ambitious proposal can be easily listed, led by the extremely high cost of building a bridge or tunnel between two underpopulated and peripheral regions of Britain and Ireland," Mr Pollak said.

"The 22.5-mile road bridge between Shanghai and Ningbo, believed to be the longest sea-crossing bridge in the world, is costing around £750m in a country with one of the industrialised world's lowest labour costs."

But he said the arguments in favour were worth hearing too. A link would provide a massive social and economic boost to both parts of Ireland and Scotland, "something a lot of people, including the Taoiseach and Northern Irish and Scottish First Ministers, view as an unadulterated good".