Economists and diplomats are cautioning that Keir Starmer's growth plan for the UK will not succeed without access to EU markets. They suggest that a Labour government led by Starmer would need to rejoin the customs union to fulfill the party's manifesto promises. A recent poll by Opinium for the Observer reveals that 56% of voters believe Brexit has had a negative impact on the UK economy, while only 12% think it has been beneficial. This highlights the importance of re-establishing ties with the EU to maximize economic growth.