Cool heads can find buying opportunities as Greek tragedy unfolds

So say the experts, after the FTSE 100 fell by 6.6 per cent in June, its worst monthly performance since May 2012, and by 3.5 per cent on Monday and Tuesday alone, after the eurozone talks broke down.

The index high was 7104 on April 27, so it would need to drop below 6400 to be hitting the 10 per cent drop seen as a technical correction.

Although long-term investing is the holy grail, sharp market movements will always prompt trading decisions for many, good or bad.

Hargreaves Lansdown senior analyst Laith Khalaf said: "Investors would be well-advised to keep their heads, particularly when all about them are losing theirs.

"The UK stock market is still only marginally lower than the start of the year, and with such low yields on cash and bonds, it still represents an attractive home for long term money. Indeed when there is weakness in stock markets it's usually the time to buy in, not sell out."

Shaun Port, chief investment officer of Nutmeg, commented: "Capital controls are hurting the Greek economy very badly, forcing Syriza to adapt its strategy. A willingness to compromise ahead of the referendum is now evident, but European leaders seem to believe that the capital controls will push Greeks to vote 'yes' and are not prepared to do much before Monday. The EU is not ready to jettison Greece from Europe whether it leaves the euro or not."

Mr Port added: "We believe the backstops put in place in the past three years will limit contagion to European banks should Greece leave the euro. Our main concerns are that confidence is hit, dampening the recovery, and/or we see deposit flight in Spain or Italy. However, it's likely the ECB will do whatever it takes to guarantee continued growth."

David Thomson, chief investment officer at VWM Wealth in Glasgow, said: "I believe the situation in Greece represents a buying opportunity as I believe Greece is now well insulated from the rest of Europe if things go wrong. The uncertainty is creating the opportunity and while an exit would be damaging in both the short and longer term and will most likely delay European recovery, there are also compensating positives such as interest rates around the globe and inflation staying lower for longer."

Asked to pick a fund it would be Threadneedle European Select, MrThomson said, while assets to avoid would be UK Gilt funds, seen as a safe haven but already looking expensive.

Tim Wishart, senior investment director at Psigma Investment Management in Edinburgh, said: "We have got a few people who have been holding money back, waiting for an opportunity, the worry is of course that when the opportunity appears they still don't do it."

He added: "There is a good chance in the coming weeks that this is not a bad moment, because broadly the global economy is still doing alright, and yet valuations are back 10 per cent from the peak." Equities were now being valued (on price-earnings ratios) at only a slight premium to the long-term average, against a background of continuing low returns elsewhere, Mr Wishart said.

Bonds, he added, carried some risks in the current Greek scenario. "Everyone tries to paper over the cracks because no-one wants to do any scaremongering, but the situation could still throw up a number of issues - liquidity could become an issue as it did at the start of the credit crunch."

Mr Port added: "Eurozone equities look really attractive on a longer term basis. Economies like Spain are putting in some solid economic performance at the moment. We could try to trade the market and go to safe haven assets like US government bonds but we think doing that will actually exacerbate losses. Those selling when European assets are down and buying highly priced government bonds are likely to see losses on those bonds."