Skip to content
CityAM
Main navigation
  • News
    • News
      • Latest Business News
      • Economics
      • Politics
      • Tech
      • Banking
      • FTSE 100 Live
      • Retail
      • Insurance
      • Legal
      • Property
      • Transport
      • Markets
    • From our partners
      • AON
      • Bayes Business School
      • Canada BIDs
      • Central London Alliance CIC
      • Destination City
      • Halkin
      • Olympia
      • Inside Saudi
      • Tottenham Hotspur Stadium
      • Santander X
      • YEAR SIX Dividend
    • Featured

      Strait of Hormuz closed over ceasefire violations, says Iran

      Aerial view of ships navigating the strategic Strait of Hormuz, highlighting its importance to global maritime trade routes

      Submit a story

      Tell us your story.

      Submit
  • Opinion
  • Sport
    • Latest Sports News
      • Sport
      • Sport Business
    • From our partners
      • The Morning Briefing: SBS x CityAM
      • Aramco Team Series
      • LIV Golf
    • Featured

      Platitudes in women’s sport are empty, patronising and offensive

      Business professionals in a conference room discussing strategy with a presentation screen displaying key market trends.

      Submit a story

      Tell us your story.

      Submit
  • Life&Style
    • Life&Style
      • Life&Style
      • Toast the City Awards
      • The Magazine
      • Travel
      • Culture
      • Motoring
      • Wellness
      • The RED BULLETiN
      • Do it with Shared Ownership
      • Media Speak Hub
    • Featured

      Fogo de Chao nominated for Best Casual Dining Toast award

      Fogo de Chão restaurant exterior with vibrant signage and bustling entrance at popular city location

      Submit a story

      Tell us your story.

      Submit
  • Investec
  • Events
  • Latest Paper
Wednesday 19 October 2016 9:04 am

Leaked government documents reveal £75bn cost of hard Brexit

By: Jake Cordell

Add as a preferred source on Google

Theresa May has come under fire for regurgitating pre-referendum economic warnings to claim leaving the EU Customs Union would cost the UK £75bn and inflict travel chaos across the country.

According to The Guardian, the Prime Minister has circulated papers to top cabinet colleagues on her Brexit planning committee outlining the potential mutli-billion pound cost of a hard Brexit, as the divisions among her inner circle continue to rumble.

Chancellor Philip Hammond, who has come under attack this week by unnamed senior figures for attempting to "undermine Brexit", was forced to deny speculation he has threatened to quit yesterday. Separately, leading City figures told CityAM the government's new departments for international trade and exiting the EU are not listening to the needs of London's financial sector.

The calculations, sent to May's close-knit team of Brexit advisers, which includes Hammond, David Davis, Liam Fox and Boris Johnson, claim the UK economy would be 4.5 per cent smaller by 2030 if it leaves the Customs Union as part of any Brexit deal. Such a hit would leave the UK £75bn worse off.

Read more: Should the City be worried about the EU's new Brexit negotiator?

However, the claims which are arrived at by taking the average assessment obtained from the controversial work undertaken by the Treasury before the vote, along with pre-23 June studies from the National Institute of Economic and Social Research (Niesr) and the London School of Economics (LSE), were dismissed by several experts.

"The idea that leaving a customs union will cost 4.5 per cent of GDP is farcical," Ryan Bourne, head of public policy at the Institute of Economic Affairs told CityAM

"Any short-term costs would be vastly outweighed by the ability to extricate ourselves from the customs union’s Common External Tariff – a protectionist wall which currently raises prices for consumers of manufactured and agricultural goods by around 20 per cent."

Theresa May and Philip Hammond arrive for last month's G20 summit. Do they still see eye-to-eye on the UK's Brexit plan?

Shanker Singham, director of economic policy at the Legatum Institute said: "The estimate assumes the worst. This would be the cost of tariff increases as we leave the customs union and some extra admin, but [the figure] assumes that we don’t succeed in negotiating anything more with other countries in the form of other free trade agreements."

The analysis on the costs of leaving the Customs Union also argued the UK's infrastructure networks could not handle the additional administrative pressures needed to set up a new fully-fledged border between the UK and the EU. 

Sam Bowman, executive director at the Adam Smith Institute also questioned the figures: "The pre-referendum Treasury analysis suggested full exit from the Single Market would cost us around six per cent of GDP so it's quite astonishing if two-thirds of that comes from customs checks and rules of origin.

"It's perfectly reasonable to use pre-referendum estimates to calculate the cost of Brexit, although one important factor doesn't seem to have been factored into those, which is Bank of England monetary easing."

Share this article

  • Facebook
  • X
  • LinkedIn
  • WhatsApp
  • Email

Similarly tagged content:

Sections

  • Markets & Economics
  • News

Categories

  • Business
  • Economics
  • Politics

Trending Articles

  • As it happened: Stocks sink after Fed and Bank of England opt for hawkish hold; Oil price tumbles

  • FTSE 100 Live: Pound dips and stocks slip as Andy Burnham victory triggers political uncertainty

  • City investors raise alarm on Burnham’s Chancellor pick

  • Inheritance tax enquiries surge to six-year high after HMRC clampdown

  • More Big Four blues as Deloitte plans to slash UK audit roles

More from CityAM

  • SpaceX lands record $75bn raise as Wall Street braces for mega debut

    Tech
    Tech billionaire Elon Musk has been asked to serve in Donald Trump’s cabinet. (Photo by Apu Gomes/Getty Images)
  • Treasury still has £5bn to spend on Covid-19 – taking total bill to £385bn

    Economics
    The UK economy has seen low growth under Chancellor Rachel Reeves.
  • Starmer weighs cut to EU student fees in bid for Brexit reset

    Politics
    Prime Minister Keir Starmer speaks at a press conference addressing future leadership rumours, wearing a navy suit and tie.
  • ‘Dual squeeze’: FCA approvals for e-money licences plummet

    Fintech
    Klarna IPO announcement showcased on Times Square billboard, highlighting fintech growth and market anticipation
  • Rich List reveals scale of wealth exodus from Britain

    Wealth
    Monaco
  • Innocent smoothie boss bananas for EU red tape reset

    Retail
    Innocent Drinks logo featuring a simple, playful design with bold colors, symbolizing the brands fresh, healthy beverage e...
  • Streeting’s EU Plan would cost our hard-won relationship with Trump

    Opinion
    Wes Streeting addressing media at a public event, wearing a suit and tie, with a focused expression and microphones visible
  • Space X to allow British investors to buy into blockbuster IPO  

    Investing
    Elon Musk's SpaceX IPO

CityAM Canada — business, markets and opinion for Canadian readers.

Sections

  • Business
  • Markets
  • Tech
  • AI
  • Economics
  • Opinion
  • Cities

Company

  • About
  • Contact

Legal

  • Terms of Use
  • Privacy Policy
  • Cookie Policy
© 2026 CityAM Canada. All rights reserved.
Terms · Privacy · Cookies