TOPSHOT - Britain's Prime Minister Theresa May arrives at the European Council in Brussels on October 17, 2018. - British Prime Minister Theresa May is due to address a summit of European Union leaders in which Brexit negotiations are expected to be top of the agenda. (Photo by EMMANUEL DUNAND / AFP)        (Photo credit should read EMMANUEL DUNAND/AFP/Getty Images)
EMMANUEL DUNAND/AFP/Getty Images
TOPSHOT - Britain's Prime Minister Theresa May arrives at the European Council in Brussels on October 17, 2018. - British Prime Minister Theresa May is due to address a summit of European Union leaders in which Brexit negotiations are expected to be top of the agenda. (Photo by EMMANUEL DUNAND / AFP) (Photo credit should read EMMANUEL DUNAND/AFP/Getty Images)
Now playing
02:42
The future of Brexit remains uncertain
Myanmar Bago killing Hancocks pkg intl hnk vpx_00002309.png
Myanmar Bago killing Hancocks pkg intl hnk vpx_00002309.png
Now playing
03:39
Eyewitnesses recount bloody crackdown in Bago, Myanmar
MAY LEWIS via Reuters
Now playing
00:49
Here's why this river turned white
Hong Kong national security education day Lu Stout W&T intl hnk vpx_00013016.png
Hong Kong national security education day Lu Stout W&T intl hnk vpx_00013016.png
Now playing
01:42
Hong Kong police showcase 'Chinese-style goose-stepping'
brazil coronavirus jair bolsonaro rio de janeiro Darlington pkg intl ldn vpx_00003012.png
AFP
brazil coronavirus jair bolsonaro rio de janeiro Darlington pkg intl ldn vpx_00003012.png
Now playing
02:43
Last week, coronavirus killed 3 people every minute in Brazil
WASHINGTON, DC - APRIL 15: U.S. President Joe Biden announces new economic sanctions against the Russia government from the East Room of the White House on April 15, 2021 in Washington, DC. Biden announced sanctions against 32 companies and individuals that are aimed at choking off lending to the Russian government and in response to the 2020 hacking operation that breached American government agencies and some of the nation's largest companies. (Photo by Chip Somodevilla/Getty Images)
Chip Somodevilla/Getty Images
WASHINGTON, DC - APRIL 15: U.S. President Joe Biden announces new economic sanctions against the Russia government from the East Room of the White House on April 15, 2021 in Washington, DC. Biden announced sanctions against 32 companies and individuals that are aimed at choking off lending to the Russian government and in response to the 2020 hacking operation that breached American government agencies and some of the nation's largest companies. (Photo by Chip Somodevilla/Getty Images)
Now playing
06:49
Biden imposes new sanctions on Russia
CNN's Becky Anderson speaks with Fatima Gailani, an Afghan women's rights activist and government peace negotiator, about her views on the planned withdrawal of foreign troops from Afghanistan.
CNN
CNN's Becky Anderson speaks with Fatima Gailani, an Afghan women's rights activist and government peace negotiator, about her views on the planned withdrawal of foreign troops from Afghanistan.
Now playing
03:49
Afghan negotiator: I'm worried about withdrawal without peace
Prince Charles and his wife Camilla, Duchess of Cornwall, took in flowers left in tribute to his recently deceased father Prince Philip. The flowers had initially been left outside Buckingham Palace but were moved over the road to Marlborough House.
UK Pool via ITN
Prince Charles and his wife Camilla, Duchess of Cornwall, took in flowers left in tribute to his recently deceased father Prince Philip. The flowers had initially been left outside Buckingham Palace but were moved over the road to Marlborough House.
Now playing
01:56
Prince Charles and Duchess of Cornwall view tributes for Prince Philip
screengrab afghanistan taliban
AFPTV
screengrab afghanistan taliban
Now playing
03:50
How Taliban may run Afghanistan after US troops withdraw
Tokyo Olympics 100 days countdown Essig pkg intl hnk vpx_00000000.png
Tokyo Olympics 100 days countdown Essig pkg intl hnk vpx_00000000.png
Now playing
03:14
Growing concerns over Tokyo Olympics Covid-19 safety measures
screengrab japan fukushima daiichi
IAEA
screengrab japan fukushima daiichi
Now playing
02:31
Japan plans to release treated Fukushima water into sea
SUEZ, EGYPT - MARCH 29: The container ship 'Ever Given' is refloated, unblocking the Suez Canal on March 29, 2021 in Suez, Egypt. This morning the container ship came partly unstuck from the shoreline, where it ran aground in the canal last Tuesday, and later resumed its course shortly after 3pm local time. The Suez Canal is one of the world's busiest shipping lanes and the blockage had created a backlog of vessels at either end, raising concerns over the impact on global shipping and supply chains. (Photo by Mahmoud Khaled/Getty Images)
Mahmoud Khaled/Getty Images
SUEZ, EGYPT - MARCH 29: The container ship 'Ever Given' is refloated, unblocking the Suez Canal on March 29, 2021 in Suez, Egypt. This morning the container ship came partly unstuck from the shoreline, where it ran aground in the canal last Tuesday, and later resumed its course shortly after 3pm local time. The Suez Canal is one of the world's busiest shipping lanes and the blockage had created a backlog of vessels at either end, raising concerns over the impact on global shipping and supply chains. (Photo by Mahmoud Khaled/Getty Images)
Now playing
00:57
Egypt seizes Ever Given ship, asks for $900M in compensation
Taiwan has been the chief source of tension between Washington and Beijing for decades and is widely seen as the most likely trigger for a potentially catastrophic US-China war. The worry about Taiwan comes as China wields new strength from years of military buildup. CNN's David Culver reports.
PLA Air Force/Weibo
Taiwan has been the chief source of tension between Washington and Beijing for decades and is widely seen as the most likely trigger for a potentially catastrophic US-China war. The worry about Taiwan comes as China wields new strength from years of military buildup. CNN's David Culver reports.
Now playing
04:04
Dramatic videos show Chinese naval exercises amid rising tensions over Taiwan
CNN
Now playing
05:40
Unprecedented footage shows front line of Ukrainian conflict with Russia
5995404 02.09.2019 Iranian Foreign Minister Mohammad Javad Zarif attends a news conference following his meeting with his Russian counterpart Minister Sergei Lavrov, in Moscow, Russia. Iliya Pitalev / Sputnik  via AP
Iliya Pitalev/SPTNK/Sputnik via AP
5995404 02.09.2019 Iranian Foreign Minister Mohammad Javad Zarif attends a news conference following his meeting with his Russian counterpart Minister Sergei Lavrov, in Moscow, Russia. Iliya Pitalev / Sputnik via AP
Now playing
04:09
Iran accuses Israel of sabotaging nuclear site, vows revenge
Ash rises into the air as La Soufriere volcano erupts on the eastern Caribbean island of St. Vincent, seen from Chateaubelair, Friday, April 9, 2021. (AP Photo/Orvil Samuel)
Orvil Samuel/AP
Ash rises into the air as La Soufriere volcano erupts on the eastern Caribbean island of St. Vincent, seen from Chateaubelair, Friday, April 9, 2021. (AP Photo/Orvil Samuel)
Now playing
01:08
See the looming clouds of ash over La Soufrière volcano
screengrab Vanuatu villagers mourn philip
Reuters
screengrab Vanuatu villagers mourn philip
Now playing
02:03
Remote tribe worships Prince Philip as god, mourns his death
(CNN) —  

The British government has the power to unilaterally halt the Brexit process, a top European legal adviser has said, delivering a significant boost to campaigners who want the UK to remain in the EU.

In an opinion prepared for the European Court of Justice (ECJ) in Strasbourg, the advocate general said the UK could stop the two-year legal countdown invoked under Article 50.

The UK had argued that the Article 50 notification could only be withdrawn with the agreement of all 27 remaining EU member states.

Announcing his conclusion Tuesday, Advocate General Campos Sanchez-Bordona declared that Article 50 “allows the unilateral revocation of the notification of the intention to withdraw from the EU.”

Judges must now decide whether to accept the advocate general’s advice, as they do in most cases.

If they do, it gives the UK parliament another way in which to force the government’s hand. With only 16 weeks to go before the Article 50 deadline on March 29, options are running out if parliament rejects Prime Minister Theresa May’s Brexit deal.

The advocate general’s opinion comes in a case originally brought in Scotland by a cross-party group of anti-Brexit campaigners, led by Andy Wightman, a Scottish Green Party lawmaker in the Scottish Parliament. Scotland’s top court, the Court of Session in Edinburgh, had referred it to Strasbourg for a ruling.

The case was fiercely opposed by the British government, which unsuccessfully argued that the Supreme Court in London should intervene before it went to Europe.

May told her Cabinet Tuesday that Brexit would not be reversed, a spokesman said. May stressed that the advocate general’s findings were not binding on the court.

Jolyon Maugham, one of the petitioners in the case, welcomed the advocate general’s opinion, urging UK lawmakers to “search their consciences and act in the best interests of the country.”

“The decision is one that the UK can make unilaterally – without needing the consent of the other Member States. That puts the decision about our future back into the hands of our own elected representatives – where it belongs,” he wrote on Twitter.

Conservative lawmaker Dominic Grieve, a former attorney general and second referendum supporter, told the BBC the decision by the advocate general was “clearly significant.”

“Of course it doesn’t necessarily have to be translated into a judgment, but the opinion of the advocate general is often very influential in forming the opinion of the court and it reinforces something I have to say I personally always thought was probably the case.”

Asked whether the decision could lead to a second referendum on EU membership, he added: “It is certainly helpful because it removes one of the arguments which is ‘Oh well, they would never allow us to change our minds’.”

In his opinion, Sanchez-Bordona said the possibility of the UK unilaterally revoking Article 50 would be subject to “certain conditions and limits.” He noted that it must “respect national constitutional requirements,” and that would likely mean a vote in the UK parliament.

ECJ justices are expected to decide whether to accept the legal advice in the coming weeks. After that, the case will be referred back to the Court of Session in Edinburgh for a final ruling.

The decision came on the day that Theresa May begins her quest to sell the Brexit deal to lawmakers in the House of Commons.

MPs will spend the next five days debating the deal before a vote next Tuesday, which May is widely expected to lose.

Before Tuesday’s debate begins, May could face another setback, when MPs vote on whether her government should be held in contempt of parliament for failing to publish the full legal advice on her deal.