(Adds London shares, details, CEO quotes)
By Emma Rumney
JOHANNESBURG, Nov 21 (Reuters) - Weak UK banking and wealth management performances dragged on Investec's first-half profit, piling pressure on the Anglo-South African financial services firm's shares.
Investec said on Thursday the spin-off of its asset management division next year was on track, a plan that will leave it with just banking and wealth management operations.
Shares in Investec are down by almost 10% following a profit warning in September, and were around 2.5% lower in both London and Johannesburg by 0823 GMT.
Investec said its bank and wealth businesses were committed to meeting 2022 financial targets, although co-CEO Fani Titi, who will head them following the demerger, added it was hard to say when the uncertainty hurting performance would recede.
"If Brexit is sorted out and there is a level of certainty in the market... that should translate into better activity for our businesses," he told a media call.
"But we don't know when that certainty will return."
Together, adjusted operating profit of the combined bank and wealth operations fell by 4.2%, driven by an 18.9% decline at UK specialist banking and a 10.8% drop in wealth and investment.
This was offset by an 8.5% increase at its South African specialist bank, thanks to higher fee income and cost controls.
Investec said the UK specialist bank's performance was skewed by a subordinated debt restructuring that gave it a boost in the prior year.
By contrast, the asset management division, which will be renamed Ninety One and is on track to list separately in London in the first quarter of 2020, enjoyed net inflows of 3.2 billion pounds and a 6.3% growth in adjusted operating profit.
Co-CEO Hendrik du Toit, who will head that business once it is spun off, said Investec was pleased with its performance given global market volatility caused by trade tensions.
"These are the kind of environments in which firms can build market share who are focused on their clients, and in that sense we are very happy with the ... net inflows."
Investec's headline earnings per share, the main profit measure in South Africa, was 22.7 pence in the six months to Sept. 30, compared with 27.4 pence a year earlier.
The bank's adjusted basic earnings per share, which reflect profits made in the course of ordinary operations, were down 4% from 30.1 pence last year to 28.9 pence this year. (Reporting by Emma Rumney; Editing by Edmund Blair and Alexander Smith)