By Sanchayaita Roy and Pranav Kashyap

(Reuters) - British stocks were mixed on Thursday as consumer giants Unilever and British American Tobacco pressured the export-heavy FTSE 100 index, while midcap stocks were mostly stable.

The FTSE 100 index fell by 0.5%, marking its worst performance in nearly two weeks, after reaching consecutive record highs over the past three sessions.

The midcap FTSE 250 gained 0.2%.

Heavyweight Unilever lost 5.6%, logging its worst session in over three years, after the Ben & Jerry's maker gave a dour outlook. The company picked Amsterdam over London and New York as the primary listing for its ice cream spin off.

British American Tobacco slipped 8.8%, its biggest daily decline since March 2020, after the company took a 6.2 billion pound ($7.74 billion) hit from a Canadian lawsuit.

Barclays lost 4.7% after hitting its highest level since March 2011 on Wednesday. The lender announced its 2024 results and 2025 outlook earlier.

Limiting losses, Coca Cola HBC jumped 7.4% after the bottler's full-year results topped expectations.

Vistry Group gained 4.3%, one of the top gainers on FTSE 250, after Boston-based investment firm Abrams Capital increased its stake in the UK housebuilder to 10.2% from 8.2% and becomes top shareholder.

Among sectoral moves, the aerospace and defence sector gained 1.5% after Jefferies suggested any drop due to a potential Ukraine-Russia ceasefire should be seen as a buying opportunity, with Europe expected to increase its defence spending.

Oil and gas lost 1.6% as oil prices fell more than 1% on the prospect of a peace deal between Russia and Ukraine. [O/R]

Activist investor Elliott Management acquired nearly a 5% stake in oil major BP.

The pound ticked up after data showed Britain's economy unexpectedly picked up in late 2024.

"The economy is hardly in good health and another quarter bumping along the bottom is not the growth the government has promised," said Danni Hewson, head of financial analysis at AJ Bell.

Bank of England Chief Economist Huw Pill told Reuters the central bank needs to move cautiously with cutting interest rates because the long process of wrestling down inflation is not yet complete.

(Reporting by Sanchayaita Roy and Pranav Kashyap in Bangalore; Editing by Eileen Soreng and Christina Fincher)