The FTSE 100 index climbed above the 5,500 mark at the close of the last trading sessions before Christmas.
Trading closed four hours earlier than usual as the UK prepares for the Christmas holiday.
The blue chip index closed at its highest level, 5,513, since December 12.
The UK was further buoyed by news affirming its status as a safe haven as 10-year gilts yields touched 2%, the lowest level since the 1950s.
The biggest climber towards the end of the session was Tullow Oil, up 3.1% to 1,385p. It was joined at the top by medical devices company Smith & Nephew, which rose 2.5% to 606p and utilities company National Grid, which also increased by 2.5% to 618p.
Publisher Reed Elsevier, was also up 2.5% to 516p, while miner Antofagasta rose 2.4% to 1,228p.
Brewer SABMiller and Financial Times publisher Pearson both grew by 2.2% to 2,237.5p and 1,217p, respectively.
Lloyds Banking Group was the biggest faller dropping 0.9% to 25.62p and was joined at the botom by Royal Bank of Scotland Group, which slipped 0.3% to 20.54p.
Mexican silver miner Fresnillo and services company Serco also both dropped by 0.3% to 1,534p and 468.6p, respectively. Meanwhile, Old Mutual slid 0.2% to 135.3p.
To receive more relevant articles like this one, why not sign up to our briefings and breaking alerts by clicking here.