The blue-chip FTSE 100 closed 0.1% up, led by personal goods makers <.FTNMX3760>, food and drug retailers <.FTNMX5330>, real estate investment trusts <.FTNMX8670> and travel and leisure stocks <.FTNMX5750>.
The domestically focused mid-cap FTSE 250 ended 0.4% higher, boosted by soft drinks maker Britvic Plc, which jumped 6.4% as it forecast annual adjusted operating profit ahead of market expectations.
Britain said the situation regarding trade talks with the EU remained unchanged, as both sides exhorted the other on Tuesday to compromise to avoid a fast-approaching disruptive finale to the five-year Brexit drama that would add to the economic pain from the coronavirus crisis.
"There's a lot of wrangling and political posturing but traders are not too scared as it's all part of the process to get a deal," said Stefan Koopman, senior market economist at Rabobank.
"The market is still pricing that a deal will happen and so we have to suffer through this as the waiting game continues and time clearly is not limited."
New business restrictions due to surging COVID-19 infections and a stalemate over Brexit have pressured UK markets this month, with analysts also warning of a further slowdown in domestic economic growth.
A recent Reuters poll found the Bank of England was likely to supplement its quantitative easing war chest next month to offer more support to a faltering recovery.
In company news, airlines group IAG rose 6.9% as rapid outbound COVID-19 testing for passengers was launched at London's Heathrow Airport in an effort to re-open restricted routes and boost traffic for airlines.
Bellway Plc fell 3.7% after the homebuilder reported a 64.3% drop in annual pretax profit.
Petra Diamonds Ltd tumbled 17% after the diamond miner abandoned plans to sell the business in favour of a debt-for-equity restructuring.
(Reporting by Devik Jain in Bengaluru; Editing by Uttaresh.V and Alex Richardson)
By Devik Jain