London - May's government published a "great repeal bill" to incorporate EU law into British law after Britain leaves the European Union, which Brexit Secretary David Davis said would allow a Brexit "with maximum certainty, continuity and control."

"It is one of the most significant pieces of legislation that has ever passed through parliament and is a major milestone in the process of our withdrawal from the European Union," Davis said of the bill, officially known as the European Union (Withdrawal) Bill.

A disappointing election 

But the heads of the devolved governments in Wales and Scotland, Labour's Carwyn Jones and Nicola Sturgeon of the Scottish National Party, said the bill showed the government has "failed utterly" to keep its promise of collaborative government.

"We have repeatedly tried to engage with the UK government on [Brexit], and have put forward constructive proposals about how we can deliver an outcome which will protect the interests of all the nations in the UK, safeguard our economies and respect devolution," Carwyn and Sturgeon said in a joint statement.

"Regrettably, the bill does not do this," they said. "Instead, it is a naked power-grab, an attack on the founding principles of devolution and could destabilise our economies."

The Scottish and Welsh governments have both expressed concerns about the potential effects of Brexit on their regional economies. Following a disappointing snap election last month, May has made the repeal bill the centrepiece of her legislative agenda for the next two years, saying it will "provide certainty for individuals and businesses" during the Brexit process.

Her government said the bill is designed to ensure that "as far as possible, the same rules and laws will apply on the day after exit as on the day before."

Keir Starmer, Labour's shadow Brexit secretary, earlier threatened to block the bill in parliament, where May now has to rely on support from Northern Ireland's Democratic Unionist Party after losing her majority in the June 8 election.

Facing a strong opposition

Starmer told Thursday's Guardian that he was "putting the government on notice" that it would face strong opposition in parliament unless it amends the bill to allow greater parliamentary scrutiny and protection of workers' rights.

Human rights groups also criticized the bill, with Liberty UK and Amnesty International saying it "includes worryingly broad powers for ministers to alter laws without parliamentary scrutiny and contains no guaranteed protections for human rights."

"If the repeal bill passes in this state, people in the UK will lose rights after we leave the EU," said Martha Spurrier, director of Liberty. "It is that simple and the stakes are that high."

"The broad powers that the repeal bill grants ministers to change our laws are dangerously vague - they must not be used to roll back human rights that are in place to protect us all," said Kerry Moscogiuri, campaign director for Amnesty UK.