The head of the City of London Corporation said the government must give reassurance to investors that ministers will not violate international law in order to ensure future investments in the UK.
Business District political leader Catherine McGuinness explained the current Brexit negotiations and the government said violating international law could prove problematic.
She told the PA news agency that the recording "gave people a pause to think". She added, "But the rule of law is the bedrock of our system and we are undermining it at our risk."
Their comments came when the company revealed a poll conducted by Downing Street ahead of the recent Brexit comments that found 99% are still interested in investing in the city.
The city also suffers from a labor shortage. Ministers are desperate to get staff back to their offices and are putting pressure on senior executives, as well as chairmen and women, to encourage workers to move to the city centers.
Ms. McGuinness said it was important for employees to return, although she admitted that building trust in employees will be important.