Scotland’s polling expert Sir John Curtice has weighed in with his election prediction as votes begin to be counted across the country.

Speaking on BBC’s Good Morning Scotland programme, the Strathclyde University professor estimated that the SNP are on course to take home 64 seats in total – one short of a majority.

Sir John took into account the last five opinion polls, suggesting it “is all going to turn” on nine marginal, opposition held seats.

He also estimated that Alex Salmond’s intervention with the Alba Party “probably cost the SNP some list votes”.

He told the programme: “If you take the five opinion polls that were conducted in the last week or so of the campaign, they suggest that on average the SNP are running at 49% on the constituency vote, although much lower – about 38% - on the list.

“The Conservatives are narrowly ahead of Labour – about 22% conservatives to 21% for Labour on the constituency vote - but the Conservatives enjoy a comfortable four-point lead on the list vote and that’s going to be the crucial one so far as seats are concerned.

“It looks like the Greens are heading for a record performance, they’ve been running at about 10% in the final polls.

“Liberal Democrats are at around the six to seven points as last time. The Alba Party under Mr Salmond running at around three.”

Sir John added: “If you take all of those numbers and you do the dangerous game of trying to predict what the outcome might be, you get to 64 SNP seats – which really means there is a 50% chance the SNP will get an overall majority, but equally a 50% chance that they might fail.

“Indeed, it’s probably all going to turn on the outcome in nine really marginal, opposition held seats – some held by Conservative, some held by Labour – but all with majorities of less than five points.

“If the national polls are roughly right, it is a question of how many of those seats the SNP manage to pick up and that’s one of the things you really cannot tell from national polls, whether that’s going to happen or not.”

The polling expert rejected suggestion that there had been much movement in the polls over the course for the campaign, adding the results are “virtually identical” for most parties compared to the second half of March.

However, he added: “The Labour party made a bit of ground in the constituencies according to the polls.

“The SNP certainly fell back on the list and basically are down by around three points - and low and behold the Alba Party have already got 3% according to the polls.

“Mr Salmond’s intervention has probably cost the SNP some list votes, although at the end of the day it is the performance of the Greens that is primarily responsible for the fact that the SNP list is more than ten points adrift of its constituency vote.”

Counts in more than half of Scotland’s parliamentary constituencies are to begin today, as the country awaits the outcome of its strangest election since devolution.

Votes in some 46 of the 73 constituency seats will be counted from about 9am on Friday, with the first results expected from noon.

It is anticipated all 46 should be declared by Friday evening.

Then, from about 9am on Saturday, the remaining 27 constituency seats will be counted, after which the regional seats will be allocated.