The Prosperity Institute warned rejoining the EU customs union could cost up to £40 billion per year.

• Keir Starmer has suggested reassessing the UK’s relationship with the EU.

• Rachel Reeves called stronger EU ties the UK’s “biggest prize.”

• The Prosperity Institute estimates:

  • 0.5% GDP reduction in the first year of rejoining.

  • 1.35% GDP reduction within five years.

  • Equivalent to £30–£40 billion annual lost output.