European markets rose despite the resignation of Italian Prime Minister Matteo Renzi after a heavy defeat in Sunday's vote (4 December) for constitutional reform.
The FTSE 100 Index lifted 22.2 points to 6753, as traders shrugged off fears of a eurozone crisis, betting that the No vote would have less effect than the UK's Brexit poll, or Donald Trump's election as US President. The FTSE 250 Index rose 13 points to 17448.2.
Across Europe Germany's Dax was more than 1% higher, while the Cac 40 in France lifted by 0.7%.
IG market analyst Joshua Mahony said: "European markets have been surprisingly resilient this morning, as initial fears of another eurozone crisis have been largely brushed aside.
"Sharp depreciation in the euro and European indices have been swiftly reversed, bearing more than a passing resemblance to the UK referendum and US election results."
However, in Italy the MIB in Milan was down by 1.5% as the country looks set to enter a period of political uncertainty.
In afternoon trading the biggest risers in the FTSE 100 Index were Antofagasta (+20p to 713.5p), Tesco (+4.8p to 211.5p), BHP Billiton (+27p to 1331p), Burberry Group (+25p to 1437p) and ITV (+2.7p to 169.6p).
The biggest fallers in the FTSE 100 Index were Fresnillo (-42p to 1156p), Randgold Resources (-185p to 5640p), Polymetal International (-14p to732.5p), Severn Trent (-31p to2096p) and United Utilities (-12.5p to 870p).
In afternoon trading the biggest risers in the FTSE 250 Index were Kaz Minerals (+12.6p to 388p), Debenhams (+1.9p to 58.2p), Vedanta Resources (+27.5p to 873.5p), Computacenter (+21p to 749.5p) and Amec Foster Wheeler (+11.8p to 455.5p).
The biggest fallers in the FTSE 250 Index were G4S (-11.1p to 232p), Euromoney (-48p to 1101p), Cranswick (-75p to 2156p), Grafton Group Units (-17.5p to 514.5p) and James Fisher & Sons (-54p to 1625p).