LONDON, Dec 8 (Reuters) - Britain’s huge financial sector will never again have the same access to the European Union as it did when the country was a member of the bloc, the EU’s financial services chief said. Brexit makes it “even more urgent” for the EU to develop its own capital market to cut reliance on the City of London, Europe’s biggest financial centre, Mairead McGuinness said. Britain’s full access to the EU ends on Dec. 31 when a transition period that followed Brexit in January expires. So far the bloc has only granted time-limited UK access for derivatives clearing and securities settlement, to allow for an orderly migration of the activities to the bloc. Many banks, asset managers and insurers in London have opened hubs in the bloc to avoid disruption to clients from limited direct access from the UK. Financial services are not part of floundering talks between London and Brussels on a free trade agreement, to which Prime Minister Boris Johnson said on Tuesday that Britain might call a halt without a deal being reached. “The end of the transition period will lead to significant changes and this will happen whether there is a deal, or indeed whether there is no deal in these coming hours,” McGuinness told an event held by French asset management industry body AFG on Monday evening. “A third country will never have the same rights and benefits as an EU member,” McGuinness said. “We also need to regulate, supervise and manage our own risks and our own financial stability, and this is not possible if there is reliance on a third country. “Complementarity with the City of London? Absolutely. Reliance? No.”