The Prime Minister was said to have quietly scrapped the tradition before changing stance
Downing Street has confirmed the St George's flag will fly from No10 from Wednesday to mark England's advancement in the World Cup, after Sir Keir Starmer was earlier accused of being a "plastic patriot".
Asked by journalists about the flag, a spokesman for the Prime Minister said: "It's our flag, heritage and values. We will be flying our flag for knockout matches; we will put it up on Wednesday."
England play the Democratic Republic of Congo on Wednesday at 5pm, marking the Three Lions' first match of the knock-out stage of the tournament.
Sir Keir is known to be a huge football fan and is a regular at Arsenal's Emirates Stadium.
The U-turn to fly the flag comes after Sir Keir was branded a "plastic patriot" when it emerged he had quietly scrapped the 16-year tradition before changing stance.
It was originally reported No10 would not drape the English flag across Downing Street for the World Cup, despite pledging to "fly our flag proudly" on St George's Day.
Former Prime Ministers have either flown the flag on match days or for the entire tournament, a tradition which began in earnest under David Cameron in 2010.
Then-Local Government Minister Grant Shapps at the time urged councils across the country to show their support "to avoid accusations of being overzealous or spoilsports".
Both the St George's flag and Union Jack have been at the centre of dispute in recent years, with critics branding the adornment of flags as "far right" and "racist", rather than patriotic.
The Raise the Colours movement has since aimed to reinstate the flag and restore civic pride in communities, with periods of international football bringing with them a boost in support for the flags.
Theresa May declared No10 was "proud to fly the flag" to cheer on the Three Lions in 2018, with Downing Street receiving a red-and-white makeover for the Euro 2024 final at the start of Sir Keir's premiership.
The street was draped in England's flag the just last year after the Lionesses beat Spain to retain the Women's Euros.
Initially suggesting he backed the flying of flags in public, Operation Raise the Colours did, for a time, see the Prime Minister tread more carefully around the subject.
His spokesman earlier said: "He has pride in the flag, he thinks it is important that we do have pride in our flag, it represents our history and our heritage and our values. That is why he has an England flag in his flat."
However, a few months later, Sir Keir hatched plans to "reclaim the flag" from the "far-right" after activists raised banners across the country.
An earlier speech saw the Prime Minister claim the Union Jack and St George's Cross represent a "symbol of inclusion".
On St George's Day this year, Sir Keir went on to declare: "It's our flag. It belongs to us, and we will fly it for the values that we believe in."
The flag has been absent for all three of England's World Cup group stage fixtures, with plans to fly the flag scrapped for England's clashes with Croatia, Ghana and Panama.
Sir Keir is said to have planned to fly the Saltire if Scotland made it to the knockouts – a prospect that never manifested after the nation got the boot on Sunday night.