BLACKFRIARL The highs and lows that are the post Brexit binge

Meanwhile the pound continues to droop, despite the short-lived bounce following news that MPs would be allowed to debate the Brexit plan.

Analysts point out that the FTSE’s rude health isn’t based on a reflection of how Britain’s blue chips company are actually performing - it’s solely a reaction to the plunge in sterling.

Laith Khalaf, senior analyst at Hargreaves Lansdown, said: “This is a hollow victory for the UK stock market because it has been based on movements in the currency markets rather than any positive reassessment of the productivity of UK-listed companies.”

Looking on the bright side, the FTSE’s strength will cheer investors and people with pensions and ISAs as it improves their wealth.

“As long as interest rates remain low, the stock market is really the only game left in town for long term money,” said Mr Khalaf.

“Of course, every silver lining comes with a cloud, and a weaker currency means anyone heading abroad for half term this October is probably in for a nasty shock when they hit the bureau de change. Indeed with some airport outlets giving less than a euro back per pound coin handed over, it makes sense to plan ahead and get the best rate possible.”

In the longer term, the weak pound will raise challenges in a number of sectors, particularly retail which imports a lot of goods.

Discount clothing retailer Primark has said it intends to absorb the higher cost of imports to maintain its position as a bargain destination, but fashion chain Next said it would pass on higher costs to consumers.

Next, one of Britain’s biggest clothing retailers, has estimated that the weaker pound will push up its costs by 5 per cent next year if it cannot find cheaper suppliers. Based on its experience in 2010, after sterling’s last big fall, passing a 5 per cent price rise on to shoppers would reduce the volume of sales by 5.5 per cent.

There will also be pain for the supermarkets, which import around 40 per cent of their goods. One beneficiary could be Bradford-based Morrisons as it makes more of its own food in the UK than its rivals.

Meanwhile the political rollercoaster and backtracking means that global investors are getting twitchy about the UK.

​Ryan Myerberg, portfolio manager at Janus Capital, said: “For a period of time the UK was an attractive place to put capital, but that has certainly changed for us and a number of other people that I speak to.”

The post-Brexit volatility across UK markets has been best captured by the wild swings in the pound, which Reuters described as more akin to an emerging market currency than the fourth biggest and most traded currency on the planet.

Sterling has fallen ​nearly ​18 per​ ​cent since the referendum and five per​ ​cent in the last five days. It’s at a 31-year low against the dollar, its lowest on a trade-weighted basis since the 1970s​. This is a bigger fall than that seen during the 2008 financial crash, when the pound dropped 16​ per cent and​ is almost as large as the devaluation triggered by Black Wednesday in 1992, when the pound plunged by 19​ per cent​ after leaving the Exchange Rate Mechanism.

​​Brian Tomlinson, senior fixed income portfolio manager at Allianz Global Investors​, said:​​​ ​“Sterling should eventually go lower. How much lower though?”

​So in such a state of uncertainty, what should investors do?

Mr ​Khalaf​ ​has some sage advice: “I suspect there will be a great deal of noise around the markets for some time, but I would encourage investors to shut it out and focus on getting back to basics; namely to maintain a diversified portfolio, make sure your investments are held as tax efficiently as possible, and make sure you are getting good value from the funds you hold​.”

Hold on to your hats​ though. The Brexit road will undoubtedly contain a lot more twists and u-turns.