The City of London needs a watertight Brexit transition deal by the year-end for banks to plan ahead and avoid a “cliff edge” hurting the economy, the financial district’s mayor will say.

Lord Mayor of London Andrew Parmley will tell the annual City Banquet on Wednesday evening that government backing for a transition deal of about two years between leaving the European Union and the start of new trading terms “will be our bridge to the future”.

“But the idea must become reality, translated into a legal agreement before the end of the year,” Mr Parmley will say in remarks released in advance to the media.

“The longer this is left, the more it damages all our futures – not only in the UK, but the economy right across the EU.”

Mr Parmley, who holds the ceremonial post of mayor of the municipal authority that oversees London’s financial district, will say the financial sector needs to know more about the “final state” or future trading terms with the EU.

“How can the UK’s most profitable industry be expected to programme its satnav without knowing the destination?”

Banks in London are already announcing they will move some staff and activities to the EU before Britain’s departure from the EU in March 2019 to be sure of serving European customers.

Business news: In pictures Show all 13 1 /13 Business news: In pictures Business news: In pictures Flybe collapses Airline Flybe has collapsed. All future flights on the Exeter-based airline have been cancelled – leaving more than 2,300 staff facing an uncertain future, and wrecking the travel plans of hundreds of thousands of passengers. The chief executive, Mark Anderson, said: “Europe’s largest independent regional airline has been unable to overcome significant funding challenges to its business. AFP via Getty Business news: In pictures Future product placement will be 'tailored to individual viewers' Marketing executives say that product placement in films and televison shows on streaming services such as Netflix may be tailored to individuals in future. For instance, if data shows that a viewer is a fan of pepsi, a billboard in the background of a shot would host an advert for pepsi, while for a viewer known to have different tastes it could be for Coca-Cola Paramount Business news: In pictures Corbyn wishes Amazon a happy birthday In a card sent to Amazon CEO Jeff Bezos on the company's 25th birthday, Labour leader Jeremy Corbyn writes: "You owe the British people millions in taxes that pay for the public services that we all rely on. Please pay your fair share" Business news: In pictures No deal, no tariffs The government has announced that it would slash almost all tariffs in the event of a no-deal Brexit. Notable exceptions include cars and meat, which will see tariffs in place to protect British farmers Getty Business news: In pictures Fingerprint payment NatWest is trialling a new bank card that will allow people to touch their hand to the card when paying rather than typing in a PIN number. The card will work by recognising the user's fingerprint NatWest/PA Wire Business news: In pictures Mahabis bust High-end slipper retailer Mahabis has gone into administration. 2 Jan 2019 Mahabis Business news: In pictures Costa Cola Coca-Cola has paid £3.9bn for Costa Coffee. A cafe chain is a new venture for the global soft drinks giant PA Business news: In pictures RIP Payday Loans A funeral procession for payday loans was held in London on September 2. The future of pay day lenders is in doubt after Wonga, Britain's biggest, went into administration on August 30 PA Business news: In pictures Musk irks investors and directors Elon Musk has concluded that Tesla will remain public. Investors and company directors were angry at Musk for tweeting unexpectedly that he was considering taking Tesla private and share prices had taken a tumble in the following weeks Getty Business news: In pictures Jaguar warning Iconic British car maker Jaguar Land Rover warned on July 5, 2018 that a "bad" Brexit deal could jeopardise planned investment of more than $100 billion, upping corporate pressure as the government heads into crucial talks AFP/Getty Business news: In pictures Spotif-IPO Spotify traded publically for the first time on the New York Stock Exchange on Tuesday. However, the company isn't issuing shares, but rather, shares held by Spotify's private investors will be sold AFP/Getty Business news: In pictures French blue passports The deadline to award a contract to make blue British passports after Brexit has been extended by two weeks following a request by bidder De La Rue. The move comes after anger at the announcement British passports would be produced by Franco-Dutch firm Gemalto when De La Rue’s contract ends in July. The British firm said Gemalto was chosen only because it undercut the competition, but the UK company also admitted that it was not the cheapest choice in the tendering process. Business news: In pictures Beast from the east economic impact The Beast from the East wiped £4m off of Flybe’s revenues due to flight cancellations, airport closures and delays, according to the budget airline’s estimates. Flybe said it cancelled 994 flights in the three months to 31 March, compared to 372 in the same period last year.

Mr Parmley criticised “economically illiterate calls” of those who want to put up cross-border barriers - Britain opposes plans by Brussels that could force the clearing of euro-denominated trades to move from London to the EU after Brexit.

The banquet in the “Square Mile” will also hear speeches from the heads of the Financial Conduct Authority, and the Bank of England’s Prudential Regulation Authority.

Mr Parmley will say there is a need to maintain existing financial rules, remarks that will take a swipe at those who have suggested Brexit could be an opportunity to ditch some EU-originated regulation to improve competitiveness.