Chancellor John Healey was caught on video chug-a-luggin a pint behind the counter at the Two Chairmen pub in Westminster, London, following evening festivities for the fiscal plan.
Treasury civil servants inside the drinking establishment urged the politician to finish the drink after he poured it himself.
Video footage captured him tossing his red tie over his shoulder while finishing the beverage.
Healey subsequently inverted the glass and lifted it over his head in celebration after finishing every drop.
This lighthearted event occurred hours following the formal unveiling of the budget earlier that day.
Healey presented his inaugural financial plan, increasing taxes and public spending instead of enacting swift reductions to welfare expenses.
He detailed increased taxes on financial institutions, property owners, and investors, alongside fresh energy sector changes.
The Chancellor announced that fixed gas standing charges will be eliminated next year for roughly 23million households.
Additionally, the fuel duty freeze continues for the 16th consecutive year at 52p per litre, preventing a scheduled rise planned for January 2027.
A permanent tax-free mileage allowance increase to 55p was also established.
