London’s standing as a global financial centre is at risk unless the immigration system is urgently reformed, according to a new report from TheCityUK.

“Losing this could undermine Britain’s position as the world’s leading financial centre,” TheCityUK’s Chief Executive, Miles Celic, said in a statement.

As reported by the Reuters news agency, the financial sector is quick to remind the government that it is Britain’s biggest economic sector, raising more than 70bn pounds annually in taxes.

Other sectors like health and agriculture are also calling for unhindered access to international hires after Brexit. The government is mindful, however, that many of those who voted to leave the EU in Britain’s 2016 referendum want tougher controls on immigration.

Across Britain 7.5% of banking and related professional staff are European citizens and 4.7% are from non-European countries, rising to 16.9% and 11.4%, respectively, in London where one in four staff in the sector are non-UK citizens.

According to Reuters, banks, insurers, asset managers, and the lawyers and accountants that support them, can currently hire from across EU states without visas, but must use the “Tier 2” work visa system for citizens from outside the bloc.

If Britain fails to secure a bilateral agreement with the EU on the movement of people, the sector will have to use the Tier 2 system for all non-British hires.

Applications for certain categories of Tier 2 visas are routinely oversubscribed and rejected due to caps on numbers, the report said.

The report calls for the British government to make the Tier 2 system more “dynamic” by introducing a “shortage occupation list” that reflects actual shortages being faced, including digital and cyber security skills, reported Reuters.

Tim Loughton, a lawmaker on parliament’s home affairs committee which scrutinises government immigration policy, said the recommendations were “practical and doable” and could feed into a committee report on post-Brexit immigration.