With Britain firmly on the path to exiting the European Union, major insurers are moving forward with their plans to establish bridgeheads in key European cities to try and ensure that they keep unfettered access to EU business.

In late March, U.K. Prime Minister Theresa May triggered Article 50 of the European Treaty, setting in motion the process, likely to take two years, by which the U.K. formally will leave the EU following a referendum vote in June 2016.

At the same time as the so-called Brexit was triggered, Lloyd’s of London announced that it has chosen Brussels as the location for an insurance company aimed at allowing its syndicates continued access to the European market once the United Kingdom leaves the European Union.

The decision by Lloyd’s followed U.S. insurer American International Group Inc.’s announcement that it plans to set up a base in Luxembourg once the U.K. leaves the EU to retain so-called passporting rights, which enable insurers and reinsurers based within the EU to write business in all 27 members states without the need to be regulated in each one.

It is not yet known the extent to which U.K. insurers will retain those rights — if at all — once the U.K. leaves the EU.

Lloyd’s announced last year that it would examine the options available to it to set up an insurance structure within the EU to enable syndicates to have continued access to business from the EU and the three countries in the associated European Economic Area.

Several of the larger managing agencies that operate syndicates at Lloyd’s said they also would consider setting up operations in Europe.

Lloyd’s became one of the first major U.K. financial institutions to announce its post-Brexit plan when it said it had decided to set up an insurance company in Brussels.

The operation is expected to be ready to underwrite business for the January 2019 renewal season, subject to regulatory approval.

“It is important that we are able to provide the market and customers with an effective solution that means business can carry on without interruption when the U.K. leaves the EU,” Inga Beale, CEO of Lloyd’s, said in announcing the move.

“Brussels met the critical elements of providing a robust regulatory framework in a central European location, and will enable Lloyd’s to continue to provide specialist underwriting expertise to our customers,” she said.

John Nelson, chairman of Lloyd’s, said that “tens” of Lloyd’s staff members would either move or be hired locally once the company is set up.

Sources said that Brussels had been chosen ahead of other EU domiciles including Dublin, Luxembourg and Malta in part because of its location within mainland Europe, and because of its strong regulatory framework, among other factors.

In a note to members of the Lloyd’s Market Association, which represents managing agents at Lloyd’s, Mel Goddard, the LMA’s market liaison and underwriting director, said that a key factor in the choice of location for a European insurance company had been the ability to retain key features of the Lloyd’s franchise.

The LMA was part of a cross-disciplinary working group set up to examine the options available to the market.

Ms. Goddard said that a solution that emulated as closely as possible the Lloyd’s market model — for example the ability to cede 100% of premium written back to a managing agent — had been a key factor in the decision.

Other important considerations, she said, had been the robustness of the local regulatory environment, as well as keeping costs low, since the Brussels company will be an additional operation to the existing Lloyd’s structure, and flexibility.

AIG in March announced that it would set up a base in Luxembourg to service EU business once the U.K. exits the EU.

“This is a decisive move that ensures AIG is positioned for whatever form the U.K.’s exit from the EU ultimately takes,” Anthony Baldwin, CEO of AIG Europe, said.

In a statement, AIG said that “the majority of the business we write out of the Luxembourg entity will be in continental Europe, and geographic proximity is a benefit.”

“Luxembourg is a core member of the European Union and has a stable economy and a well-respected insurance regulator,” it added.

Meanwhile, Beazley P.L.C. has applied for a license to set up a company in Dublin, a location where it already has operations.

Hiscox Ltd., another major Lloyd’s player, said it is in talks with regulators in Luxembourg and Malta about setting up an insurer once Brexit takes place.