Gordon Brown has signalled his support for a nuclear deterrent

He made the comments in an exclusive BBC Scotland interview almost a year after the G8 summit in Gleneagles.

Churches have criticised the chancellor for his support of retaining a nuclear deterrent and said the billions could be better spent on aid and debt relief.

But Mr Brown said it was possible for the government to do both.

Speaking on Wednesday, Prime Minister Tony Blair told MPs a decision on replacing Trident would be taken later this year.

The chancellor can take a different view, but it is a different view from the church that he was brought up in The Reverend Alan McDonald Church of Scotland moderator

It has been estimated that it could cost up to �25bn to replace the missile system and the Vanguard submarines which carry them.

Last week Mr Brown signalled that he wanted to keep and renew Britain's independent nuclear deterrent.

That led to condemnation from Scottish churches.

Scotland's most senior Roman Catholic, Cardinal Keith O'Brien, and the Church of Scotland's moderator, the Reverend Alan McDonald, shared a platform in Glasgow on Tuesday evening.

Cardinal O'Brien said nuclear weapons were a stumbling block to peace.

'Great credit'

Mr McDonald asked how many lives could be saved by �25bn if it was devoted to debt relief rather than buying weapons.

He said the chancellor was due "great credit" for his part in the Make Poverty History campaign.

However, Mr McDonald said: "What was the point in having a Make Poverty History campaign a year ago that the churches so enthusiastically joined in with and then at the end of the day here we are proposing to spend �25bn on a useless weapon?

You must have defence and security in the modern age and you must be able to help those in greatest need Chancellor Gordon Brown

"That seems to me to be close to insanity.

"The chancellor can take a different view, but it is a different view from the church that he was brought up in."

Speaking in the Kirkcaldy church where his father preached, Mr Brown defended his stance.

He said: "We have managed to ensure the defence and security of this country in a world where we are prey, unfortunately, to terrorist threats.

"At the same time, we have managed to show that we can double overseas aid, we can increase investment in Africa three-fold, we can create a vaccination facility that will ensure that five million children live rather then die.