Boris Johnson pledged on Friday that he would give up drinking until Brexit is solved.
It wasn't clear how long he planned to stay dry but today on a visit to a pub in Wolverhampton the Prime Minister gave into temptation.
He was asked to take a sip of a beer after pulling a pint, recalled his promise on Friday, but then proceeded to "wet his whistle."
Pub landlord Dave Buck jokingly held the pint aloft and offered it to customers for £80, but there were no takers.
Mr Buck also joked that Mr Johnson's pint-pulling technique was "terrible"and said the PM would not be offered a job behind the bar.
The moment Boris met NHS staff and revealed his promise on Friday.
It is not the first time such a promise has been made and the policy is not without controversy.
Labour, meanwhile, has vowed to scrap the public sector pay cap and provide decent housing for forces and their families by ending the reliance on the private rented sector.
It will also consult on creating a representative body to give a voice for service men and women, and end privatisation – with a review on outsourcing contracts.
The Liberal Democrats have committed to scrapping settlement fees for forces personnel born outside Britain.