The FTSE 100 index of top British-listed companies have closed the day's trading at a record high for the second time in a month.
Stocks nudged up by 0.07% or 5.03 points throughout the day - enough to push it to a record closing high of 7,560.35 points.
The previous maximum was set just three weeks earlier, on October 12, when the index hit 7,556.24 points.
Markets are being driven forward by the weak pound.
The UK currency has slumped as Brexit negotiations progress without any sign of a breakthrough.
The pound has also failed to snap back from after the decision by the Bank of England to raise interest rates for the first time in a decade.
The weak pound can benefit international firms listed in London, which tend to do better when when foreign currencies are stronger than sterling.
News of the latest rise has added to concerns that the market could be becoming overvalued - and may drop back at some point in future.
Laith Khalaf, a senior analyst at Hargreaves Lansdown, said: "Of course the FTSE 100 hitting another record high does prompt questions about share prices overheating, though the UK's headline index is a poor barometer of the value in the stock market."