Boris Johnson has announced plans for legislation to make it easier to rip up EU regulations and protections, amid criticism from Conservative MPs that the government has not taken sufficient advantage of Brexit.

The plans claim to cut £1bn in red tape expenses for businesses, but Johnson gave no firm details on which regulations are intended to be repealed or enhanced, instead stating five principles that would be applied, including the value of sovereignty and creating new markets.

Critics said Johnson must make clear whether he intends to target employment protections, and pointed out that businesses and government have already faced billions of pounds of costs as a result of additional red tape due to Brexit itself.

Sarah Olney, the Liberal Democrat spokesperson for business, said: “If this is the best Boris Johnson can muster up to save his job, then he is in big trouble. Try telling the thousands of lorry drivers stuck in queues at Dover that red tape is being cut.”

A Labour source said: “The key question for the government is which of the proposed changes in regulation depend on the passage of this bill, and if the answer is none, what other changes are they planning that do? Until they can explain all that, we have to ask what the point of this bill is.”

Johnson, who is battling to prevent a no confidence vote in the wake of multiple revelations of lockdown parties in Downing Street, has been criticised in private meetings with MPs that the government has not demonstrated how it is taking advantage of perceived post-Brexit freedoms.

The new law – called the “Brexit freedoms” bill – is intended to make it easier to amend or remove some of the bridging law kept on the statute book after Brexit. No 10 said that, as it stands, much of that regulation would require primary legislation to remove it, and the new bill could shortcut that process.

Downing Street said it would release a public catalogue of all retained EU laws to determine if they are beneficial to the UK.

In a statement announcing the new bill, two years after Britain’s exit from the bloc, Johnson said: “Getting Brexit done two years ago today was a truly historic moment and the start of an exciting new chapter for our country. The plans we have set out today will further unleash the benefits of Brexit and ensure that businesses can spend more of their money investing, innovating and creating jobs.”

“Our new Brexit freedoms bill will end the special status of EU law in our legal framework and ensure that we can more easily amend or remove outdated EU law in future.”

The attorney general, Suella Braverman, said it was right that there was new scrutiny of the laws. “We can move away from outdated EU laws that were the result of unsatisfactory compromises within the EU, some of which the UK voted and lobbied against – but was required to adopt without question,” she said.

“These rules often had limited meaningful parliamentary scrutiny and no democratic legitimacy in the UK at all. It is vital that we take the steps necessary, in this parliament, to remove unnecessary rules altogether, and where regulation is needed, ensure that it meets the UK’s objectives.”

The government will also publish a new riposte to critics who claim little advantage of Brexit has been taken, with a new document titled The Benefits of Brexit: How the UK Is Taking Advantage of Leaving the EU.

It will claim that reforms have led to a more agile digital and AI sector and a less burdensome data rights regime compared with the EU’s GDPR. It will also claim that there have been benefits in changing clinical trials, strengthening environmental protections and establishing a domestic subsidy regime.

Emily Thornberry, the shadow attorney general, said the government was not taking advantage of one key aspect of leaving the EU – that it can cut VAT on energy bills, as Labour has been demanding.

“The British public overwhelmingly support Labour’s proposed change, and it is time the government started listening,” she said.