SCOTTISH ministers have accused their UK counterparts of a deliberate attempt to frustrate devolution as it emerged they could have just weeks to draw up financial plans for the coming year – or face a £12 billion cliff-edge.

Chancellor Sajid Javid has announced the UK Budget - including the Scottish Government's allocation - will be set on March 11, following a delay in the run-up to the general election.

Under the normal process, this leaves Scottish Finance Secretary Derek Mackay with less than three weeks to get his tax and spending plans for 2020/21 through Holyrood, rather than the usual few months.

Mr Mackay insisted the UK Government had given “no prior notice before announcing their budget date, showing complete disrespect for the Scottish Parliament and our budget process”.

Meanwhile, a spokesman for the Scottish Government said officials would be unable to collect income tax in Scotland if rates are not passed by March 31.

He said: “The single biggest danger, however unlikely, is if the Parliament doesn’t pass a rates resolution in time, then there is no authority to collect income tax. That’s the absolute top line risk.”

However, he later stressed: “Our position is we have to pass an income tax rates resolution at some point.

“Don’t misunderstand me – I’m not suggesting in any way that the Government thinks this is an outcome that is at all possible to actually envisage in the real world.

“It’s simply the reality of the Act. We have to get this done.”

Income tax raised around £12 billion in Scotland in 2018/19.

The spokesman said the date of March 11 would make it “extremely difficult” for the Scottish Parliament to carry out its work.

He said: “This is not the way people foresaw devolution and the relationship with Westminster working – where, without a care for the realities of Scottish fiscal processes, the UK Government has set out a timeline that looks almost deliberate in its attempt to frustrate devolution.”

Mr Mackay said he had received no response to his repeated calls for clarity on the budget date, including a recent letter sent to the Chancellor just two weeks ago.

He added: “The UK Government’s approach to the Scottish budget is completely unacceptable – the delay of over four months since their original planned date cannot be blamed on the general election, and suggests a disregard for devolution and a lack of fiscal responsibility.

“The failure of the UK Government to publish its budget at an earlier time means we do not have clarity on the funding available for our schools, hospitals and other vital public services.

“Despite this, we remain focused on introducing a Scottish budget for 2020/21 at the earliest practical opportunity.

“We will continue to engage with the Scottish Parliament and the Scottish Fiscal Commission over how best to respond to what are exceptional circumstances, and an announcement on the proposed date for introduction of the new Scottish Budget will be made in due course.”

Mr Mackay said there would be "profound consequences" from the March 11 date, and accused the UK Government of not caring.

He suggested an "exceptional, bespoke process" would be needed to pass the upcoming budget in time.

He told MSPs: "It appears to me that the UK Tory Government has given up on the Union altogether."

Mr Mackay spoke out as experts at the Chartered Institute of Taxation warned the Scottish budget process will have to take place "at breakneck speed, with little room for manoeuvre".

The only alternative would be for Mr Mackay to "go it alone" and outline his tax and spending plans for the forthcoming year beforehand.

But Alexander Garden, the chairman of the Institute's Scottish technical committee, said in those circumstances Mr Mackay would be "constrained" by not knowing exactly how much cash Scotland would receive from the UK Government.

Council umbrella body Cosla described the March 11 date as “extremely worrying”, and argued it puts essential services at risk.

March 11 is the current deadline for councils to set local tax rates for 2020/21.

Cosla resources spokeswoman Councillor Gail Macgregor said: “By delaying the UK budget until mid-March, the UK Government is putting thousands of essential public services at risk of going without funding.

“Cosla is calling for the Scottish Government to do all it can to mitigate this risk.

“Local authorities carry out a complex and hugely important role in our society.

“As the employer for 10 per cent of Scotland’s workforce and a procurer of over £6.3bn in goods we are the key economic driver for communities across the country. Any delay to our budgets means that these services are put at risk.

“The UK Government’s decision runs the risk of delaying the Scottish Government’s budget.

“This significantly impedes the ability for local authorities to formulate their own budgets meaning Scotland’s communities are disadvantaged.

“COSLA is calling on the UK Government to provide Scotland with an increased settlement so that the Scottish Government can provide Councils with enough funding to deliver the vital services that our communities rely on.”

Scottish Greens co-leader Patrick Harvie said: “For the UK Government to set out its budget on March 11 shows contempt for devolution, and for local government.

"That is the day Scottish councils are legally obliged to set their council tax rates.

"This has left Derek Mackay with the unenviable task of proposing a budget for Scotland without knowing exactly how much money he has, or what the tax forecasts will be.

“I urge him to publish an early draft of the budget as soon as possible, even if it needs to be amended later in Parliament.

"I also urge all other opposition parties to engage constructively for a change and bring positive budget proposals to the table."