Extending Britain's departure date from the European Union would only be a "sticking plaster" if deep-seated issues are left unresolved, City of London financial district chief Catherine McGuinness said today.
Prime Minister Theresa May is in Brussels today to ask the EU for a delay to Brexit, which is legally set to take place on March 29.
The UK parliament has twice rejected the divorce settlement negotiated by May and Brussels, but she could push for a third vote next week.
"It's imperative we avoid a no-deal Brexit," Catherine McGuinness told a City & Financial conference today.
"An extension would be welcome and let's hope our EU partners agree to that," she said.
"But it would only be a sticking plaster unless the deep underlying issues are resolved and we actually make progress. To me it feels like we are caught in something of a hamster wheel," she added.
Catherine McGuinness said she expected London's strengths as a global financial centre to remain.
However, she said it also appeared that financial services had been "thrown under a bus" in terms of Britain's efforts to secure a divorce settlement with the bloc.
UK financial services minister John Glen told the conference that the sector had every right to feel frustrated with Britain's failure so far to secure a divorce settlement with just a week to go before Brexit Day.
Despite parliament having so far rejected Britain's divorce settlement, it was important to recognise "how unlikely" a no-deal Brexit was, Glen said.