TREASURY Chief Secretary Danny Alexander yesterday accused the Scottish government of failing to come clean on the price tag for setting up an independent Scotland.

But Scottish finance minister John Swinney rejected “ludicrous” Treasury claims that it could cost billions of pounds.

Mr Alexander said: “The Scottish government is trying to leave the UK but it won’t tell anyone how much the set-up surcharge is for an independent Scotland.”

Treasury estimates, based on a study of Quebec, suggest that it could cost up to 1 per cent of a country’s GDP to establish the systems required to run a newly independent state.

In Scotland’s case, this would mean a £1.5 billion tax bill — equivalent to £600 per household.

Mr Alexander said the Treasury would publish figures on Wednesday which take into account factors including oil revenues, the ageing population, the costs of creating the new state, Scotland’s fiscal starting position and the Scottish government’s policy commitments.

It quotes independent research by the Institute for Government and the London School of Economics which puts the average cost of setting up a new policy department at £15 million.

Applying this figure to 180 new departments for Scotland totals £2.7bn.

The Treasury said that, while it had used a more conservative figure in its own analysis, £2.7bn was “reasonable.”

Westminster analysis has put the costs of a new benefit system at £400m and setting up a new tax system at as much as £562m.

Meanwhile, it estimates the costs of implementing key independence policy proposals such as childcare and cuts to air passenger duty and corporation tax to at least £1.6bn each year.

Mr Swinney hit back: “This is a deeply flawed analysis, underlined by the ludicrous and palpably false claim that an independent Scotland would need 180 government departments — something we have never claimed.

“Much of the infrastructure needed for an independent country already exists and Scottish taxpayers already pay their fair share for all devolved and reserved services.”