The SNP has an "historic opportunity" to win the majority of Scottish seats in the forthcoming general election, party campaign director Angus Robertson declared.

With less than six months until voters go to the polls to elect a new UK government, he said the SNP was in "amazing shape".

While nationalists lost the independence referendum, the debate over Scotland's future has re-energised politics north of the border.

The SNP now has more than 85,800 members, and is ahead in the Scottish opinion polls.

The party currently holds six Scottish seats at Westminster, and the largest number of MPs it has ever returned is 11 back in 1974.

Mr Robertson, who is also the SNP Westminster leader, claimed it is possible the party could win a majority of the 59 Scottish constituencies.

He told the annual conference in Perth: "The SNP has an historic opportunity to win this forthcoming election."

He added: "The SNP is in amazing shape going into these elections, our poll ratings are amazing, our membership numbers are unprecedented - we have more members than all the other political parties in Scotland put together

"We need to work as hard as we can to elect SNP MPs the length and breadth of Scotland.

"Now, for the first time we can actually think about winning Westminster parliamentary seats in parts of Scotland we never ever thought was possible, and we need to get on with that."

He told activists there was as "lot at stake" in the election, and said: "We must do everything to defeat the UK coalition parties and their austerity agenda that is so hated in Scotland and elsewhere in the UK. We must also ensure that we replace the Labour dinosaurs."