SECURITY STAFF at the Houses of the Oireachtas yesterday refused entry to a group of opponents of the Corrib gas terminal who had travelled from Co Mayo to attend an Oireachtas committee.

The group of 15 Shell to Sea supporters travelled to Dublin at the invitation of Fianna Fáil deputy leader Éamon Ó Cuív to attend a hearing of the Oireachtas Committee on Communications, Natural Resources and Agriculture about offshore exploration licences.

An Oireachtas spokeswoman said the group was turned away on foot of a long-standing rule that forbids access to anyone demonstrating outside the gates of Leinster House on a particular day.

However, while campaigners against the gas terminal mounted a small protest outside Leinster House, members of the group said they had not participated in this picket.

Spokeswoman Maura Harrington said the group met Mr Ó Cuív in a hotel across the road and then walked over to Leinster House, where they learned they would not be admitted. “We came 200 miles in good faith but once again, our good faith has been thrown back at us.”

At the committee, officials of the Department of Energy and Natural Resources defended the licensing regime.

Principal officer Ciarán Ó hObain acknowledged that companies that make discoveries tended to do well under the Irish regime. But he said the chances of making a find were low, so overall it was a relatively high-risk investment for the companies involved.

Out of 132 wells drilled in Irish waters, only four have resulted in a commercial discovery. The cost of drilling a well ranges from $30 million (€22 million) to $120 million depending on location.

Petroleum specialist Noel Murphy said there was a huge lack of data about deep water areas. Ireland would need to be drilling five wells a year in order to have a good chance of finding oil. At the moment, an average of only one well a year is being drilled.

Successive reviews of the tax regime for offshore discoveries have seen corporation tax rates halved and royalties abolished. Tax is payable on profits after exploration costs have been written off.

Mr Ó hObain said it was wrong to compare Ireland with major producers like Norway, where the tax take is 78 per cent. No new commercial discoveries have been made in Irish waters since 2007.