The FTSE 100 edged 0.1 percent higher and the FTSE 250, which is more domestically focussed, was up by 0.6 percent at 0940 GMT.
Barclays, Royal Bank of Scotland and Lloyds were all higher with CMC Markets analyst Michael Hewson attributing gains to hopes that MPs could agree a possible next course of action which could lead to a softer Brexit.
That, and strong half-year results from midcap homebuilder Bellway, sparked gains in housebuilders, which are considered to be particularly Brexit-sensitive.
Persimmon, Barratt and Taylor Wimpey were among the biggest risers on the main bourse.
Prime Minister Theresa May is also set to address her Conservative MPs, possibly to set out a timetable for her departure to win parliamentary support for her controversial Brexit deal after being heavily defeated twice in parliament.
Sterling lost ground amid all the Brexit uncertainty.
"Time is running out though and without parliament coalescing around a majority view, the default is still no-deal," said Neil Wilson, Markets.com analyst.
But companies with a greater exposure to China including HSBC and Burberry advanced in early deals, while miners also rose as most base metals were higher with investors focussing on tight inventories and the resumption of U.S.-Sino trade talks.
Struggling department store chain Debenhams surged more than 50 percent to 3.7 pence, below the 5 pence a share possible buyout offer from Mike Ashley's Sports Direct. Sports Direct gained nearly 3 percent.
"Mike Ashley has clearly decided it’s double rather than quits on Debenhams. The potential 5p offer would be a generous one for shareholders, but it comes with strings attached for Debenhams, in particular appointing Mike Ashley as CEO," Laith Khalaf, Hargreaves Lansdown analyst, said.
Among midcaps, cyber security firm Avast slipped 5 percent after a heavily discounted share sale while Georgian lender TBC Bank slumped 7 percent.
Bellway rose 2.3 percent after saying trading in the first six weeks since the start of February has been strong as it reported a rise in first-half earnings and hiked dividend.
Meat packaging firm Hilton Food added nearly 2 percent after it reported higher annual earnings and said it believed it was "sufficiently resilient" to withstand the Brexit uncertainties.
(Reporting by Muvija M and Yadarisa Shabong in Bengaluru; Editing by Keith Weir and Alexandra Hudson)