THE Yes campaign for Scottish independence has suffered a double poll blow with the pro-UK forces enjoying respective leads in two surveys of 28% and 26%.

An Ipsos Mori poll of 1000 people put those against independence on 59% and 31% in favour; the highest support for Scotland staying in the UK since August 2011.

An online snapshot of 1236 adults by the Tory fundraiser Lord Ashcroft today puts the anti-independence vote on 56% and the pro-independence vote on 30%.

The surveys come as Michael Moore, the Scottish Secretary, this week claimed the Better Together campaign was winning the arguments on independence.

He pointed to the two Whitehall papers on independence, which UK Government insiders believe have blown serious holes in the SNP administration's arguments.

The next paper, on financial services, is due out in the next fortnight. Coalition sources have warned of "potentially terrifying" effects of independence on investments, life insurance policies and whether Scotland could withstand another banking crisis.

It is expected to say that borrowing costs would increase in an independent Scotland and, consequently, mortgage and insurance costs would rise while pension values would fall.

The Ipsos Mori poll showed among those certain to vote, 59% would vote no, up four points since February, while 31% would vote yes, down three points. One in 10 Scots were undecided.

Among those certain to vote and who have definitely decided how they will vote, the no vote leads the yes vote by 67% to 33% – with a 5% swing in favour of the no vote since February.

Alistair Darling, the leader of the No campaign, welcomed the Ipsos Mori survey as "another very encouraging poll" but warned against complacency.

A spokeswoman for Yes Scotland responded by insisting there was a better way for Scotland, adding: "We are confident that as people focus in on the choice they will be making in September 2014 — between a Yes future and a No future — that more and more Scots will join us in saying Yes."

Meantime, the Ashcroft poll, gives a 56%/30% split against independence but when don't knows and won't vote are excluded, this grows to 65%/35%. When broken down into age groups, the snapshot shows the largest gaps are among the young – 18 to 24-year-olds are 75% to 25% opposed to independence – and the old – those over 60 are 76% to 24% opposed.