DANNY Alexander will this week demand that the SNP produces its first "realistic analysis" of the cost of a Yes vote in the independence referendum.

In a speech in Edinburgh on Wednesday, the chief secretary to the Treasury will also attack the SNP's White Paper on independence for its "over-optimistic assumptions" about oil revenue. The Office for Budget Responsibility, the UK Government's fiscal watchdog, estimates oil revenue at around £3.2 billion for 2016, while the SNP government puts it at £7.9bn.

The Treasury will publish its most detailed analysis yet of the fiscal consequences of independence next month. It will set out "the impact of having to absorb the higher spending and lower tax caused by declining oil revenues, an ageing population, the Scottish Government's uncosted policy pledges and the set-up costs of independence in a much smaller budget," the Treasury said.

It has also analysed the SNP's White Paper and "attempted to produce many of the calculations that were missing".

The 650-page prospectus contains no detailed estimates of Scotland's financial position after independence, with the only budget breakdown a single page referring to 2016-17 "under current constitutional arrangements".

Alexander said the White Paper held "lots of promises but nothing credible to back it up". He added: "The problems of declining oil revenues and an ageing population cannot simply be wished away - but the broad shoulders of the UK can help absorb them."

A Scottish Government spokesman said: "Scotland is one of the wealthiest countries per head in the world and is more than capable of being an economically successful independent country."