The FTSE index fell 0.46 percent to 7,462 points, with scarce impact from the Bank of England's decision to keep benchmark interest rates on hold. The decision was widely expected, with the economy slowing amid uncertainty over the country's exit from the European Union.

Mid-caps fell 0.18 percent.

HSBC, Lloyds and Standard Chartered dragged the FTSE down, tracking other global banks lower after the U.S. Federal Reserve struck a less hawkish tone than expected following its expected rate hike.

In the UK, BoE policymakers voted unanimously to keep rates at 0.5 percent, a month after raising them for the first time in more than a decade. Bank profits tend to grow when interest rates rise.

"Although inflation has jumped to its highest level in almost six years, it seems that the growing uncertainty over Brexit is likely to encourage the central bank to adopt a wait and see approach moving forward," said Lukman Otunuga, analyst at FXTM.

Lonmin soared 19 percent after South Africa's Sibanye-Stillwater agreed to buy the troubled platinum miner in a deal that valued it at about 285 million pounds.

Lonmin shareholders have seen the value of their asset slump by 98 percent in five years as it called upon them repeatedly for cash. They will end up with about 11 percent of the combined company.

"We would take this offer... Looking longer term, the offer gives Lonmin investors the haven of a larger more robust group able to fund the likely catch-up of sustaining capital over the next few years," said Peel Hunt analysts.

Elsewhere on the FTSE, BT was among the biggest gainers, climbing 2.7 percent after UBS upgraded the British telecom company to "buy" from "neutral", driven primarily by a lower pension deficit.

Mining heavyweight Rio Tinto rose 0.8 percent and energy major Royal Dutch Shell climbed 0.4 percent, supported by slight gains in oil and metal prices. [O/R] [MET/L]

Among mid-caps, Capita declined 13 percent to its lowest in 12 years after the outsourcing company signalled a difficult 2018.

Capita said it was on track to hit its full-year profit target but said upcoming work was unlikely to provide an immediate boost and that the market for major contracts was still "subdued".

Ocado inched up 0.3 percent after the online grocer suffered a slowdown in retail sales growth in its latest quarter, hurt by a shortage of drivers.

(Reporting by Danilo Masoni; editing by Tom Pfeiffer)

By Danilo Masoni