MPs have called for the Government to prepare for the impact of possible Scottish independence on UK defence.
The Commons Defence Committee made the call following an investigation into the Scottish Government's proposals for a defence force, assuming a Yes vote in the referendum next September.
The committee urged governments in London and Edinburgh to set out more information to help voters understand the implications.
The report states: "We recognise that the process of negotiation following a Yes vote would be lengthy and complex.
"For those very reasons, it would be remiss of the UK Government not to make preparations in order to inform its negotiating position.
"We recommend that the UK Government begin now to prepare for the impact of possible Scottish independence.
"It would not be wise to begin contingency planning only after the referendum.
"This does not imply that we believe there should be negotiations with the Scottish Government prior to the referendum, but rather that it would be prudent for the MoD (Ministry of Defence) to scenario-plan."
People across Britain deserve to be presented with as full a picture as possible, the report concludes.
" To date, the information published by both the Scottish Government and UK Government falls far short of requirements," it states.
MPs looked at the Scottish National Party's (SNP) blueprint for an independent army, navy and air force over the course of a year.
The report finds that the proposed £2.5 billion budget cannot be properly judged at this point.
But it calls for m ore detail on the navy and raises a number of questions about the size and scope of a Scottish army, including costs, troop numbers and base locations.
On plans for an air force, the report states: "We do not currently understand how the Scottish Government expects, within the available budget, to mount a credible air defence - let alone provide the additional transport, rotary wing and other support aircraft an air force would need."
Transition of the Trident nuclear deterrent on the Clyde could not be achieved quickly, it finds.
The Scottish Government has made the removal of nuclear weapons a key part of its independence plan.
"Even with political will on both sides, the replication of the facilities at Faslane and, crucially, Coulport (Argyll), at another site in the UK would take several years and many billions of pounds to deliver," the report states.
"Options for basing the deterrent outside the UK, in the USA or France, even in the short term, may prove politically impossible or equally costly."
MPs also considered jobs and the shipbuilding industry, concluding that the scale of the defence force would "barely provide enough work for a single yard".
Work would have to diversify in order to secure orders in open competition, the report suggests.
Overall, the defence industry would face a difficult future, according to the report.
Intelligence services in the early years of independence would rely on "goodwill" from the rest of the UK.
Committee chairman James Arbuthnot MP said: "Crucially, we are not making recommendations to the Scottish people. The decision on independence is a matter for them.
"But we do think that Scottish voters need to see answers to the questions that we are asking the Scottish Government to provide in their upcoming White Paper.
"It will be for the Scottish Government to make its case that an independent Scotland can sustain an appropriate level of defence and security."
Scottish Government veterans minister Keith Brown said UK defence policy does not work for Scotland.
He said: " An independent Scotland will have first-class conventional forces playing a full role in defending the country as well as co-operating with international partners and neighbours, something this report fails to acknowledge by ignoring key pieces of evidence.
"Decisions on Scotland's defence and security should be made by those with the strongest interest in them - the people of Scotland - and current UK defence policy is letting Scotland down.
"For example, our geographical position and wealth of offshore and other natural assets make it a priority for Scotland to secure and monitor an extensive maritime environment.
"And yet, under the current arrangements, there is not a single major Royal Navy surface vessel based in Scotland and the RAF has no maritime patrol aircraft since the scrapping of the Nimrod fleet."
He complained that "important" evidence was left out by the committee, including favourable comparisons with the Danish defence budget.
S hadow defence secretary Jim Murphy, the Labour MP for East Renfrewshire, said the SNP plan would leave Scotland unable to adequately defend its interests.
"Experts continue to line up to expose the flaws in the SNP's plans," he said.
"Industrial job losses, capability gaps, funding black holes and shrunken forces would all be the defining features of a SNP Scottish defence force."