The proposal for an underwater tunnel linking Malta and Gozo has received a lukewarm response from experts, who point out the option floated could prove unfeasible.

“Malta’s experience with tunnelling has not been very successful,” Peter Gatt, geologist and researcher at Durham University, said.

The project could end in “catastrophe” unless the geology of the seabed and underlying rock is known well, he warned, adding he knew of a tunnel job in which the costs doubled because no geological studies were carried out and problems cropped up mid-way.

His caution about the complexity and cost of the proposal was echoed by others, who doubted the tentative price tag of €150 million put on the project.

The idea, which resurfaced last week when Gozitan businessman Joseph Borg asked the Prime Minister to look into the possibility of a “permanent road” between the two islands, was followed by news that Parliamentary Secretary Chris Said would be formally presenting the proposal with preliminary studies to Lawrence Gonzi.

Dr Said called for an in-depth technical and financial assessment of the proposal and estimated that, based on similar tunnels built over the past 30 years, the project should cost in the range of €150 million.

It all depended on the geological problems faced, Mr Gatt said about the cost. In fact, the seabed that would need to be tunnelled is not that straightforward. Malta, Comino and Gozo are separated by large faults, while Gozo’s eastern flank is also densely faulted. Moreover, there are areas near Comino where the seabed is clay.

These issues could push the costs up, Mr Gatt argued, even though he conceded that “practically anything can be built anywhere, as long as there is enough money...”

The president of the contractors’ federation, Anġlu Xuereb was more categorical, insisting the idea was neither technically nor financially feasible.

“To descend to that level, you would need a really long ramp. On the Malta side, it may not be such a problem but in Gozo, you would have to start it from Għajnsielem,” he said.

“Any structural engineer would say it is impossible,” he insisted, stressing the cost would soar well above the quoted €150 million.

Retired road engineer André Zammit also doubts the economic feasibility of a tunnel 50 metres below the seabed.

He suggested that building a tube above it could work, an idea that had already been proposed about 40 years ago by the Malta Joint Group of UK Engineers, which he chaired.

Although the suggestion had not been studied in depth at the time, it looked viable prima facie and, with the technological progress made since, the feasibility could only have increased.