The Tories outspent Labour by more than £1.5 million during the general election, it has emerged.

The Electoral Commission revealed that William Hague's widely criticised campaign cost £12,769,029 - outstripping Labour's lack-lustre but victorious election bill of £11,140,019.

The Liberal Democrats, who enjoyed the most successful third party campaign since 1929, clocked up a mere £1,364,994.

One of the key elements of expenditure was Hague's round-the-country helicopter tour - which pushed the Tory leader's transport bill to £1,471,595.

While the Tories spent more than Labour on transport, Labour spent slightly more on advertising, which was the lion's share of campaign funds for the two main parties.

Labour spent £5,049,205 on advertising while the Tories spent £4,479,116.52. The Lib Dems advertising expenditure was £199,188.

It is the first time those involved in election campaigning have had to release details of their spending under the Political Parties, Referendums and Elections Act, which also limited spending when it was passed last year.

Other parties include the United Kingdom Independence Party, who spent £748,603 while Unison, the public sector union, spent £774,796.

The Scottish National Party failed to submit its figures within the six-month deadline set out in new rules on spending passed by MPs last year.

The Electoral Commission said, "We are working with the SNP to ensure their returns get back as soon as possible."

The SNP spokesman said that they had nothing to hide, saying, "Our figures are late due to an administrative delay and will be lodged shortly."