Lord Ashcroft has released a new batch of Scottish constituency polling. Full details are here. As regular readers will know, national polls in Scotland suggest an SNP landslide with no sign of the SNP lead narrowing as the election approaches. In fact the most recent Scottish polls from YouGov and TNS showed the SNP lead growing. Lord Ashcroft has previously carried out two waves of Scottish polling, both showing the SNP winning in seats that were previously thought very safe.

Across the two previous waves Ashcroft polled nineteen Labour seats, finding the SNP ahead in all except East Renfrewshire and Glasgow North East. He has also polled four Lib Dem held seats (finding solid SNP leads in three and a narrow SNP lead in Ross, Skye and Lochaber) and the one Tory seat in Scotland where he found a tie.

In this latest wave Ashcroft has returned to the five of the tighter races he polled earlier, and polled three more Lib Dem held Scottish seats for the first time. Most of the close races are no longer close – in Glasgow South West (where Labour have a 46% majority) Ashcroft found the SNP 21% ahead. In Paisley and Renfrewshire South, Douglas Alexander’s seat, he found an SNP lead of 11%. In East Renfewshire he found a 9% SNP lead – this is the seat of Labour’s Scottish leader Jim Murphy and one of the two seats where he previously found a Labour lead.

People commenting on the Scottish election seem to fall into two groups – those who expect an almost complete SNP walkover, and those who expect them to merely do extremely well, to take “only” thirty or forty seats. I think the logic of most people in that second group is simply down to the scale of the SNP landslide looking unrealistic – the belief that they can’t be doing that well. I am often the first to advise caution towards polls showing huge shifts, so it’s fair to be sceptical – with a landslide of this scale perhaps the polls could be overestimating the swing… but they are consistent across national and constituency polling, online and telephone, and if they are correct the SNP are headed for an overwhelming victory and Scottish Labour towards something close to wipeout.

The polling in the sole Tory seat in Scotland remains extremely close. In his last poll Ashcroft found a dead heat between the Conservatives and the SNP, this time he found an SNP lead of two points.

Turning to the Lib Dem held seats, last time round Ashcroft found only a five point SNP lead in Charlie Kennedy’s seat in Ross, Skye and Lochaber, that has now grown to fifteen points. He has now additionally polled North East Fife (Menzies Campbell’s seat) where he found a 13% SNP lead and East Dunbartonshire (Jo Swinson’s seat) where he found an 11% SNP lead. Finally he polled Berwickshire, Roxburgh and Selkirk – here he found a 20 point boost for the SNP, which is enough to make it into a three way marginal but not to put the SNP ahead – the poll found the Conservatives ahead on 30%, SNP 29%, LDEM 28%.

Note that the East Dunbartonshire is one of the seat where the Lib Dems have recently released their own private polling (which may or may not be a co-incidence!). Their own polling showed figures of CON 13%, LAB 16%, LDEM 35%, SNP 32%. The SNP are 8 points lower than in Ashcroft’s poll, the Lib Dems 6 points higher. I wrote about the Lib Dem’s own polling at more length here. The primary differences are that the Lib Dems prompt using candidate name, which is fair enough, and ask about how favourably people see their local MP before they ask that voting intention question, a more questionable approach. We shall see which is the better guide. The Lib Dems have not released any of their private polling for the other three Lib Dem seats Lord Ashcroft released polls for today, from which one must draw one’s own conclusions.