THE pound came under pressure after a new opinion poll suggested the outcome of the Scottish referendum remains on a knife-edge.

An ICM survey at lunchtime yesterday put support for the No camp at 51 per cent, slightly ahead of Yes at 49 per cent after earlier polls showed a shift away from Monday's surprise survey which raised the prospect of an independent Scotland.

The FTSE 100 Index was 7.3 points higher at 6807, having remained under pressure after the European Union said it would impose fresh sanctions on Russian companies in response to Moscow's actions in Ukraine.

The pound was down against the dollar, at 1.62, after it was also affected by a strong rise in US retail sales in August. Sterling fell against the euro, at 1.25.

Among details of EU sanctions against Russia disclosed today, companies will be prevented from engaging in new contracts in oil drilling, exploration and related services in Russia's Arctic, deep sea and shale oil projects.

Shares in BP, which has a near 20 per cent stake in Russia's Rosneft, were slightly lower - off 2.1p to 470.2p - although at one stage the stock jumped as high as 494p due to what is thought to have been a mistaken trade.

Supermarket Morrrisons began the session on the front foot after it issued a defiant set of results on Thursday in which it raised its half-year dividend and said it remained confident in the benefits of its three-year turnaround plan.

Shares in the Bradford-based chain rose to 179.5p near the top of the FTSE 100 risers board before closing down 1.3p at 176.5p, though rival Sainsbury's lifted 1.8p to 287.1p.

Barratt Developments was the biggest riser in the top flight as it continued to benefit from results earlier this week showing a doubling in full-year profits.

The stock was up 10p at 389.3p, while elsewhere in the property sector Rightmove was 15p higher at 2336p and Persimmon added 21p to 1369p.

Barclays rose 4.5p to 230p after it announced the appointment of John McFarlane as its new chairman from next year.

In a quiet session for corporate results, pub chain JD Wetherspoon took centre stage as it reported a three per cent rise in pre-tax profits to £79.4 million for the year to July 27.

Its shares were boosted - up 8p to 770p - after it said like-for-like sales jumped 6.3 per cent in the first six weeks of the new financial year.

Cambridge-based engineering software firm Aveva slumped by a quarter - off 548p to 1620p - after warning the first half results will show a material impact from the strong pound and also from the timing of some contract renewals.

The biggest risers in the FTSE 100 were in Barratt Developments up 10p at 389.3p, Pearson up 24p at 1178p, Barclays up 4.5p at 230p.

The biggest fallers were Associated British Foods down 56p at 2621p.