LONDON, June 21 (Xinhua) -- British government trade minister Greg Hands handed in his resignation Thursday in protest at the proposed expansion of London's Heathrow Airport.

Hands said he had no choice but to quit after May issued an instruction to Conservative MPs to vote in favor of a multi-billion dollar third runway at Britain's biggest airport.

Hands announced his decision on his social media site, saying: "As the government will be whipping the vote on Monday, this means I am resigning from the government. I wrote to the PM (May) earlier this week on how I will honor these 2017 General Election pledges to the people of Chelsea & Fulham and vote against the Heathrow 3rd runway on Monday."

The Conservative politician, who has pledged to honor his fight against the project, announced his resignation ahead of a vital debate in the House of Commons next week.

The Independent newspaper said his decision will be a big blow to May, who had tasked Hands with piloting a vital Brexit trade bill through parliament in the coming weeks.

The newspaper said Hands' decision will also pile pressure on Foreign Secretary Boris Johnson, a fierce critic of the Heathrow expansion. Johnson will miss the vote on Monday as he will be out of the country. Although Hands has resigned as a minister he will continue to serve as a backbench MP in the House of Commons, representing his London constituency.