The British government will on Thursday introduce legislation known as the Great Repeal Bill - a crucial part of its next steps towards leaving the European Union.

The move comes the day after UK Prime Minister Theresa May set the wheels of Brexit in motion by invoking Article 50 of the EU's Lisbon Treaty, officially triggering talks to leave the bloc.

Thursday's bill repeals the European Communities Act 1972 and effectively ends the supremacy of European law in Britain, transferring all EU laws currently in force into the UK statute book.

It will ensure the UK leaves the jurisdiction of the European Court of Justice.

The bill will come into force on the day the UK leaves the EU. On the current two-year timetable that will be in March 2019.

MPs will get a chance to debate and vote on the bill before it is passed into law. Brexit Secretary David Davis has said this is an important step in giving certainty to businesses, workers and consumers.

READ MORE: Article 50 - What will be negotiated

May published columns in seven European papers on Thursday to stress that a Brexit deal was "in all our interests", striking a relatively conciliatory tone before negotiations begin.

"We will continue to play our part in ensuring that Europe remains strong and prosperous and able to lead in the world," May wrote in the Irish Times.

She said Brexit was not an attempt "to do harm to the European Union or any of the remaining member states".

But she also reiterated her warning that failure to reach a trade deal would hamper security ties.

"It would be to the detriment of us all if unnecessary barriers to trade were erected," she said.

A sombre mood

Theresa Villiers, an MP with the ruling Conservative Party, told Al Jazeera: "I feel a sense of optimism and anticipation. I very much welcome the fact that the UK is going to become an independent, self-governing democracy again."

But Tim Farron, leader of the Liberal Democrats, said: "It's a blow to Europe, it's a much bigger blow to Britain, and as a patriot I want what's best for my country. I want us to stay in the EU, so I'm in no mood to give up."

The mood was sombre in Brussels as the letter invoking Article 50 was handed over.

"There is no reason to pretend that this is a happy day - neither in Brussels nor in London. After all, most Europeans, including almost half the British voters, wish that we would stay together, not drift apart," Donald Tusk, President of the European Council, said in a statement.

OPINION: Is Brexit Britain suffering from an imperial hangover?

Germany's Chancellor Angela Merkel has spoken of her desire for the UK and the EU to remain close partners, but said that there cannot be parallel talks about trade deals alongside those concerning the terms of Brexit.

"The old EU, the so-called intergovernmental EU, is dead. It doesn't work any more. It's not equipped for the 21st century, so we need to move into a political union that is equipped to respond adequately, flexibly, quickly," Sophie in't Veld, a member of the European Parliament from the Netherlands, told Al Jazeera.

Requiem for a dream

Tony Nash, chief economist and managing partner at Complete Intelligence, told Al Jazeera that the UK was fortunate not to have to deal with leaving the Euro and that, while the pound has lost value recently, the devaluation could compensate for having to pay tariffs to access the EU market.

Nash said that financial services were the biggest immediate issue for the UK and that there were questions over whether another European city could claim London's crown as the continent's financial centre.

"If you look at places like Frankfurt or Paris, they just can't compete with London as a financial centre," Nash said. "I don't think the impact on services is going to be as bad as many people have said because you just don't have the skills and capabilities on the continent that you do in London."

A recent survey, though, suggested growing pessimism in the UK over the economic impact of Brexit.

Just 29 percent of British households surveyed in March believed it would be good for Britain's economy over the next 10 years, according to IHS Markit - down from 39 percent in July 2016.

Outside parliament in London on Thursday, a choir of protesters sang the adopted anthem of the EU.

"It's called an Ode to Joy," reported Al Jazeera's Barnaby Phillips. "But for those who lost the referendum, [it is] a requiem for a dream that died."