London’s premier share index closed Thursday’s session at 7787 points – a rise of 53 on the previous day as utility and retail stocks made some ground.
It beat the previous record close of 7778, which was recorded in January before a stock market wobble.
Values sank across the world amid fears of a US-inspired trade war, that pushed the FTSE below the 7000-point barrier at one stage in March.
Its fortunes have been largely governed by the pound since the Brexit vote – with weakness in the currency boosting the earnings of its dollar-earning constituents.
Sterling has bled value in recent weeks versus the dollar, partly because of continued concern about the state of the EU divorce talks.
But mostly it has been put down to a slowing economy pushing back the likelihood of a Bank of England interest rate hike.
The pound, trading at $1.35 to the greenback on Thursday, had been at post-referendum highs before it became clear UK growth had almost ground to a halt in the first quarter of the year.
A Reuters poll of market experts in February found a consensus view that the FTSE was unlikely to hit record levels again for two years – given jitters about Brexit and market volatility.
After the new record was set Laith Khalaf, senior analyst at Hargreaves Lansdown, said: “The death of the bull market has been greatly exaggerated, not for the first time in recent history.
“The Footsie did endure a shaky start to the year, but after two months of steady climbing, has now regained and surpassed its previous high.
“A stronger dollar, a rising oil price and the postponement of an interest rate rise can all claim some credit for the recent strong showing from the stock market.
“Investing is of course a long term game, and the twists and turns along the way are less important than the final destination.
“There will come a time when the stock market will tumble again, at which point investors should take it in their stride and look beyond the immediate situation,” he concluded.