Gordon Brown's Budget will take place in April

Sam Younger, chairman of the Electoral Commission, told the Scottish National Party (SNP) the matter was outside the remit of his organisation.

But the SNP claimed the tone of his reply implied disapproval of the chancellor's decision, announced at the beginning of March.

Mr Brown's Budget speech would normally be delivered in March but was put back to 9 April, just three weeks before Scotland goes to the polls.

It's a blatant attempt to fiddle and interfere with the Scottish election from London, and it stinks Alex Salmond

The move was greeted with anger by opposition parties in the Commons at the time, where Tories accused Mr Brown of trying to mask the government's economic record and Liberal Democrats called his decision "unwise".

But Mr Younger told SNP campaign co-ordinator Nicola Sturgeon, who complained to the commission, that the matter was outside his brief.

Mr Younger said the commission's remit was limited to elections and its role was primarily advisory.

"On matters like the date of the Budget the government is under no statutory obligation either to consult the commission or to take account of its views," he said.

"At the same time the commission can legitimately be expected to express views on issues which may have an impact on the electoral process."

Disapproval claim

Mr Younger said the commission knew of no legal reason why a Budget should not be presented during an election campaign, although by "well-established convention" significant government announcements were avoided in the run-up to general elections.

"April 9 is within the formal period of campaigning for elections to the Scottish Parliament and National Assembly for Wales and it seems right that announcements relevant to those nations should be similarly avoided," said Mr Younger.

"As a general principle, the commission would wish to see as level a playing field as our political system will allow and for that reason we would not wish to see any government use its position during an election campaign in a way which might be perceived as seeking electoral advantage.

Alex Salmond questioned the government's motives

"However, the commission is not in a position to make a judgement on the government's decision to defer the date of the Budget, since there may be a range of factors involved which go beyond our remit."

But Nationalists argued Mr Younger's letter showed the commission's disapproval.

SNP Westminster leader Alex Salmond said: "It's very clear that the Electoral Commission, the guardians of fairness in our democratic process, totally disapprove of Gordon Brown holding a Budget in the middle of the Scottish Parliament campaign.

"It's a blatant attempt to fiddle and interfere with the Scottish election from London, and it stinks.

"The timing of government announcements lies outwith the remit of the Electoral Commission, which makes their willingness to criticise it all the more significant."