Britain’s FTSE 100 hit a record high on Thursday, supported by a rally in shares in Rolls‑Royce after its forecast upgrade and in LSEG after its share buyback.Rolls-Royce rose 9.1% after reporting a 40% jump in annual profit, driven by strong demand for its aero-engines and rising power needs from data centres. British aerospace and defence stocks rose to an all-time high following the results.The blue-chip FTSE 100 index closed 0.4% higher at 10,846.70 points, while the domestically focused mid-cap FTSE 250 was also up 0.4%.The FTSE 100 has climbed 6% so far in February, on pace for its eighth straight monthly rise and outperforming its U.S. and European peers, buoyed by investor bets on an additional Bank of England rate cut in March.“It is likely that the UK index’s outperformance is here to stay,” Axel Rudolph, senior financial analyst at IG, said.Despite the UK blue‑chip index’s near 22% surge in 2025, many of its companies remain on single-digit price-to-earnings ratios, making them appealing to investors looking to cut exposure to highly valued U.S. tech, Rudolph added.London Stock Exchange Group jumped 6.7% after announcing a share buyback plan at a time the company faces pressure from activist investor Elliott Management and concerns that AI will squeeze its business model.Information group RELX gained 4.6% amid a broad recovery in global software and data stocks which had been hammered earlier this month on AI disruption fears.AI bellwether Nvidia however, fell 5% as its upbeat results failed to lift sentiment for investors increasingly concerned about the returns from massive spending on AI.Investors also sifted through a slate of domestic corporate updates.Hikma Pharmaceuticals slumped 15.8% to a more-than-three-year low after the drugmaker forecast slower annual revenue growth.On the political front, Prime Minister Keir Starmer faces a big test on Thursday when voters in Manchester cast their ballots for a new lawmaker in an election that polls say is too close to call between the British leader’s Labour Party, populist Reform UK and the left-leaning Greens.