Media playback is unsupported on your device Media caption Lib Dem cabinet minister Danny Alexander: "We can move on from the Cold War postures of the past"

There are alternatives to a like-for-like replacement of the Trident nuclear weapons system, says Danny Alexander.

The Lib Dem cabinet minister told the BBC that he had handed his report on Trident to the prime minister and deputy prime minister a fortnight ago.

The Lib Dems oppose a straight renewal of Trident, but the Conservatives say it would be "foolish" to abandon it.

Mr Alexander says when the report is published "people will see there are choices available to this country".

He said the review, which was agreed as part of the coalition agreement between the two parties, had lasted two years and was seeking to say whether "complete renewal of Trident in the way previously planned is the only way to protect our country in the future".

'Dangerous world'

Trident is a sea-based nuclear weapons system, acquired by the Thatcher government in the early 1980s, made up of four submarines carrying missiles and warheads. Each component has years of use left, but they cannot last indefinitely.

The review into its replacement had not, Mr Alexander told the BBC's Andrew Marr Show, come to any conclusions.

But it would be published in a few weeks and would show "there are alternatives where we can, as President Obama said in Berlin last week, move on from the Cold War postures of the past and try and set out a new future for this country with a deterrent which is credible but where this country can play a role in supporting disarmament in the future".

The £20bn like-for-like replacement of Trident was agreed by the previous Labour government, but has since been delayed as part of the price of the Lib Dems going into coalition with the Conservatives.

TRIDENT TIMELINE 2007: MPs approve plans for renewal in Commons vote. "Concept phase" launched to assess future submarine designs and consider value for money of project

2010: Defence review decides to delay final decision on renewal to 2016

2011: "Initial Gate" procurement phase to begin. Some building materials and components of nuclear propulsion system to be purchased over five years

2016: "Main Gate" decision due to be taken. Submarine design and missile component contracts to be finalised

2028: First replacement submarine to be delivered Q&A: Trident replacement

Conservative Prime Minister David Cameron remains committed to maintaining a round-the-clock submarine-based nuclear missile system of the kind Britain has had since the late 1960s.

But the Lib Dems insisted the coalition carry out a review of cheaper submarine or land-based options, including abandoning round-the-clock patrols.

Mr Cameron stressed his commitment to Trident, which is based on the Clyde, during a visit to the west of Scotland in April.

"The world we live in is very uncertain, very dangerous: there are nuclear states and one cannot be sure of how they will develop," he told workers at a defence contractor in Glasgow.

"We cannot be sure on issues of nuclear proliferation, and to me having that nuclear deterrent is quite simply the best insurance policy that you can have, that you will never be subject to nuclear blackmail."

The Scottish National Party has said it would not allow nuclear weapons to be based in Scotland, should next year's referendum support independence, a move that would potentially add billions to the cost of replacing Trident.

Labour has said it will examine the outcome of the Lib Dem prompted review.

Shadow defence minister Kevan Jones said it was "absolutely right and necessary" for the UK to retain an independent nuclear deterrent but the cost needed to be taken into account.