Tony Blair has clashed with the Scottish National Party after he said nuclear power was "back on the agenda with a vengeance".
Mr Blair said nuclear power was back on the agenda
The prime minister also angered Scottish environmental campaigners when he refused to rule out replacing current nuclear power stations.
The SNP's Mike Weir accused Mr Blair of threatening to leave a legacy of nuclear "dumps" in Scotland.
Mr Blair said the UK could not risk being reliant on foreign energy.
The prime minister told the CBI it would be "a collective dereliction of duty" to rule out replacing nuclear power stations.
Friends of the Earth Scotland said Mr Blair was determined to see a new generation of nuclear reactors rather than clean and sustainable options.
Green MSP Chris Ballance said his party would fight "tooth and nail" to keep nuclear power out of Scotland.
Mr Blair said the UK Government must be prepared to take the decisions necessary to ensure the country does not become "entirely dependent on foreign imports of gas".
At Prime Minister's Questions on Wednesday, Mr Weir, the SNP's energy spokesman, accused the prime minister of seeking to "bounce" the country into building new nuclear power stations.
He said this was even before the "sham" of an energy review had reported and before there was any solution to the disposal of historic, let alone new nuclear waste.
"Are the Scottish communities who figured in the last Nirex report back in the frame as possible nuclear dumps?" he asked.
"Will this be your legacy to Scotland?"
In response, Mr Blair said: "We have to dispose of existing nuclear waste in any event.
Hunterston B in Ayrshire is due to close by 2011
"But if we are to address the energy security needs of this country in the future, of the United Kingdom - including Scotland - then we have to be prepared to take the decisions necessary to make sure that we don't end up in a situation where we are entirely dependent on foreign imports of gas.
"That would not be sensible in my view."
He said he did not believe nuclear power was the only solution, but added: "I do believe we have to debate very seriously whether we need to replace nuclear power stations to guarantee the future energy needs of this country, because otherwise we would be engaged in a collective dereliction of duty."
The anti-nuclear lobby has accused him of pre-judging the government's review of Britain's energy needs.
More than a third of the electricity generated in Scotland comes from its two nuclear power stations.
Hunterston B in Ayrshire is due to close in 2011 but could be kept open for a further decade to plug the energy gap.
Torness in East Lothian is expected to stay open until 2023.
The nuclear issue has divided the Scottish Executive coalition. The Liberal Democrats are against new nuclear power stations while Labour has not ruled out the option.
Energy policy is reserved to the Westminster government but the executive has said that it will not grant planning permission for new nuclear power stations while the issue of waste disposal remains unresolved.
On Tuesday, Mr Blair told the CBI annual dinner that Britain faced the prospect of being largely reliant on foreign gas imports for its future energy needs.