London (dpa) - British and EU negotiators are set to open more talks on post-Brexit trade on Tuesday, amid waning optimism after London said it planned to table legislation that could override part of Britain's EU withdrawal agreement.

Britain confirmed on Monday that it planned "limited and reasonable steps to clarify specific elements of the Northern Ireland protocol in domestic law."

Negotiations on future trade

Another cloud was cast over the planned three-day, eighth round of formal negotiations on future trade when Prime Minister Boris Johnson said Britain would end the talks in mid-October, if no agreement is reached by then, and insisted that a no-deal Brexit would still be a "good outcome" for Britain.

"If we can’t agree by then, then I do not see that there will be a free trade agreement between us, and we should both accept that and move on," Johnson said in a written statement.

He said an agreement was still possible if Brussels was "ready to rethink its current positions."

German government remained optimistic

In Berlin, spokesman Steffen Seibert said the German government remained optimistic that a deal on future trade "can be successfully concluded" if London makes concessions on the issues of fishing and fair competition rules.

After the previous round of talks last month, EU chief negotiator Michel Barnier said he was "disappointed and concerned" that Britain had refused to budge on its positions, with no progress on the contentious issue of fisheries.

Internal market bill

The Financial Times reported earlier Monday that Johnson's government would publish an "internal market bill" on Wednesday, seeking to override provisions in the withdrawal agreement on state aid and separate customs arrangements for Northern Ireland, which had been a major sticking point in negotiations over Britain leaving the bloc.

European Commission President Ursula von der Leyen said Britain was obliged under international law to stick to the withdrawal agreement, tweeting that this was a "prerequisite for any future partnership."

"[The] protocol on Ireland/Northern Ireland is essential to protect peace and stability on the island [and] integrity of the single market," von der Leyen tweeted.

transition period until the end of the year

Britain formally left the EU in January and entered a transition period until the end of the year, during which it still belongs to the EU single market and customs union.

A slim majority voted for Brexit in a referendum in 2016, when Johnson co-led the official Vote Leave campaign.